# Can over fertilizing slow plant growth?



## DaveS (Mar 2, 2008)

I have been running an experiment on a couple of my tanks for almost exactly a year in regards to fertilization and low(ish) tech tanks. Both tanks are nearly the same in parameters except for size. One is a 20g and the other is 75g. Both tanks have right around 2 watts per gallon (a bit more on the 75), Flourite substrate, and similar plants (java fern, crypts, rotala macrandra, hygro., amazon swords, etc.).

The test I made was to use the PPS Pro fertilization routine and Excel as the carbon source with 40% weekly waterchanges. The goal was to get healthy, sustained growth without worrying about rapid growth or propogation. After a year, the results were somehwat interesting. After the year was up (about a month ago), I stopped fertilizing almost completely in the 20g tank (just Excel 3x a week) and kept the 75g on the same routine. The plants in the 20g tank have become much fuller and healthier than any time in the last year. I have seen a huge increase in the plant mass in that tank, while the tank getting daily ferts is still doing quite poorly. Neither tank was really a success with the routine I was using, but I didn't expect to see the plants doing much. much better without any real fertilization at all.

My question is this: can an abundance of particular nutrients actually stunt plant growth even if the other required nutrients are available to the plants? I realize that my carbon source might be a limiting factor, but the Excel should have been giving the plants something to work with and I would think that would allow them to process the nutrients that they require. The 75g tank will be getting a new pressurized CO2 system, so the experiment is effectively over, but any thoughts on this are welcome.

Dave


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## Homer_Simpson (May 10, 2007)

Very interesting, thanks for sharing. While I cannot comment directly on your results, I have often wondered about this. My co-worker has java moss growing like a weed in his tank and ends up throwing out or giving away bucket fulls. He does not fertilize his tanks at all, breeds guppies only, no Excel, no EI dosing, no special lighting, etc., In the tanks where I have tried to keep java moss, it has always done poorly for me. The only two things that can account for this is differences in lighting and ferts. He uses the stock incandescent lighting that came with the aquarium and doses no ferts. I use 6500 K 14 watt compact fluorescent bulb(s) and follow modified EI fert dosing for my tank. Could be that java moss just does not like ferts and perhaps the same is true for other plants.


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## jargonchipmunk (Dec 8, 2008)

well "ferts" are the nutrients that all plants need to thrive. They don't all need a LOT of ferts to thrive, but they need some. Hence, the statement "doesn't like ferts" is like saying people who eat less "don't like food." I'm definitely not a chemist, so take the following with a grain of salt, spit it out, then laugh at it. Possibly, removing the supersaturation of nutrients that those particular plants weren't using a lot of made it easier for them to absorb the carbon molecules in the water?(the chief nutrient driving plant mass, following light which you didn't change)

Like I said, not a chemist...or a botanist for that matter ;-P

However, I will add that while the plants that you are using for this particular case study might react in this way, there are certain plants that we know NEED a hefty portion of key nutrients we add to our tanks. Fertilizing routines, by and large, are implemented with these plants in mind, assuming that the plants that don't NEED the larger amounts of nutrients will simply use what they do need and leave the rest for the hungry hungry hippos of the plant world. If we could target each different stem in our tanks (not that I WANT to lol) with the specific nutrients needed, we might see a faster growth rate out of the lean eaters, as you did, while still seeing the full, colorful growth from the big pigs in the tank at the same time. Unfortunately, we choose the lesser of two evils. "over"fertilizing by a smidge to allow all plants what they need so the more picky ones will thrive and not DIE versus "under"fertilizing allowing the lean eaters to grow slightly faster, and watching the other half of our tank die.

Also, your year ended one month ago. This means that you've only had one month of water changes and normal nutrient uptake to see the new growth patterns of the plants. I would definitely be interested to see what the 20 would look like versus the 75 in 11 months time having received no additional fertilization beyond that of fish mulm. 

Keep us updated, and don't think I'm trying to bash or anything. 

(oh almost forgot, ever see what happens when a normal person goes on a "starve myself for a few days diet"? They get heavier. Removing the excess that we normally uptake causes the body to go into overdrive attempting to collect all it can so that in the coming "winter" it won't starve. I wonder if it's the same for plants? Sucking up all the carbon and other nutrients in the water that they can so that when winter comes, they'll have a better chance of waiting it out til spring. Meanwhile, the 75 still gets all it has ever gotten, so the plants just laze on, uptaking as normal since there is no drought in sight. 

Warning: The above idea might just be the ramblings of a man off his chain


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## DaveS (Mar 2, 2008)

Thanks for the input.

jargon, I tend to agree with your ideas, especially that the plants in the 20g tank probably have stored nutrients that they are now relying on rather than being able to get them readily from the water column. However, this still suggests to me that there was some over-abundance of one or more nutrients that was creating some sort of a nutrient uptake problem in the tank in general. I am no botanist either (heck, I never took a biology class past high school!) so I am at a bit of a loss here.

As I stated earlier, the 75g tank will be staying on the same plan with the addition of a full CO2 system, which may show that carbon was the limiting factor. The 20g tank I will keep an eye on and update in a few months time. Perhaps dropping the dosing rate is a better plan than just stopping completely.

Dave


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## Homer_Simpson (May 10, 2007)

jargonchipmunk said:


> ....the statement "doesn't like ferts"...


O.k. saw do you have an explanation as to why my friend's java moss does and continues to proliferate without ferts. By the way, his setup has been up and running for several years so this is not a new phenomena of stored up nutrients or anything as you put it.

Although I have had no success, many folks have had success with Diana Walstad's natural planted tank setups, where there is no water column fertilization and the mulm served to provide sufficient nutrients for the plants. The same for SCMurphy's minerlized top soil substrate where the only thing dosed in minute quantities has been potassium and in come cases only after 3 months, without plant nutrient deficiency issues or poor plant growth. In that case people with such setups warn against dosing water column ferts indicating that attempts to do so would often result in algae outbreaks. In such cases I can see how a nutrient rich substrate may be responsible but that still does not explain why java moss on plain gravel in a tank full of guppies would do well unless the fish waste and mulm was providing sufficient nutrients and extra ferts not being necessary. 

I am not trying to bash you, but just trying to understand without the semantic jargon attack.


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## davemonkey (Sep 21, 2008)

Some nutrients in excess can cause an inability of plants to absorb another particular nutrient. (Excess nutrient 'x' blocks the absorption of nutrient 'y'. ) 

I'm not a botanist either, so please don't ask me to explain it.  Anyhow, I believe that may contribute to why some plants do poorly in hardwater or in high potassium waters.

-Dave


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## taekwondodo (Apr 16, 2006)

Definitively, yes. You can over-fertilize a plant.

Although houseplants are somewhat different, put 3x the miracle grow and feed it for a few months to your Pothos (or something else). Leaves will "burn" and start dying along the edges... Tomatoes will do the same thing - with later leaves start coming out curled and twisted and completely deformed (and almost unrecognizable as a tomato plant).

I would say that the same is possible with aquatics, and I used to get similar-looking symptoms on the leaves on my alternanthera. I cannot say this was directly due to too much NO3, but when I made adjustments (reduced NO3 and changed a few other non-CO2 related things) - the leaves straightened out and I haven't seen the problem since.

- Jeff


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## Hoppy (Dec 24, 2005)

The last word from Tom Barr on this is that only terrestrial plants will be harmed by over fertilizing. Eventually you can add so much of a fertilizer to aquatic plants that they are salt damaged, but that is far above the dosages we use.

With PPS Pro you would have to be dosing more than double the recommended dosages to even be dosing what, for EI, is normal dosing. I think you would have to spill the whole bottle into the tank to do much harm to the plants, if then. (Obviously this wouldn't be true for a 5 gallon tank.)


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## imeridian (Jan 19, 2007)

Hoppy said:


> Eventually you can add so much of a fertilizer to aquatic plants that they are salt damaged, but that is far above the dosages we use.


The dead fish might be a pretty good warning sign before that would happen too. :icon_eek:


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## DaveS (Mar 2, 2008)

Hoppy said:


> The last word from Tom Barr on this is that only terrestrial plants will be harmed by over fertilizing. Eventually you can add so much of a fertilizer to aquatic plants that they are salt damaged, but that is far above the dosages we use.
> 
> With PPS Pro you would have to be dosing more than double the recommended dosages to even be dosing what, for EI, is normal dosing. I think you would have to spill the whole bottle into the tank to do much harm to the plants, if then. (Obviously this wouldn't be true for a 5 gallon tank.)


I have read that as well. I am not saying that the plants are being damaged by excess nutrients, just that the growth is somehow being inhibited. I can say for certain that I had better and healthier plants with a once a week dose of Flourish than I have seen in the last year of using PPS Pro (in this particular type of tank). I am just trying to figure out why. I will note that in full CO2 tanks, PPS Pro has worked well for me.

Dave'


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## Homer_Simpson (May 10, 2007)

DaveS said:


> I have read that as well. I am not saying that the plants are being damaged by excess nutrients, just that the growth is somehow being inhibited somehow. I can say for certain that I had better and healthier plants with a once a week dose of Flourish than I have seen in the last year of using PPS Pro (in this particular type of tank). I am just trying to figure out why. I will note that in full CO2 tanks, PPS Pro has worked well for me.
> 
> Dave'


Why not set up a seperate control tank and dose Tom Barr's estimative Index. I have a lot of respect for Edward as well as Tom Barr and the issue of differences between algae and plant growth where both methods have been used has been raised before. Generally, people who tried estimative index, including myself, had better plant growth and less issues with algae than those who tried PPS-Pro. And that is surprising, if you buy the possibility of the possible effects of overfertilizing considering PPS-Pro is a much leaner method. Like, I said the only plant that has done sh*tty for me with either method has been java moss and it always comes back to fertilization after I rule out all other possible variables. I don't need a control tank as my friend's tank where it grows like a weed is in essence the control tank.


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## DaveS (Mar 2, 2008)

Homer_Simpson said:


> Why not set up a seperate control tank and dose Tom Barr's estimative Index.


That isn't a bad suggestion. I have stayed away from EI in lower tech tanks mainly because I thought a leaner method made more sense, as well as the fact that changing 50% of the water in larger tanks is not a viable option for me. I could try changing a smaller tank (such as the above mentioned 20g tank) over to EI to see if there is a noticeable difference. I could be completely backwards in my thinking, and perhaps there is a limiting nutrient in a leaner method that is creating the problem rather than an excess.

Dave


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## Homer_Simpson (May 10, 2007)

DaveS said:


> That isn't a bad suggestion. I have stayed away from EI in lower tech tanks mainly because I thought a leaner method made more sense....
> Dave


That is true, but keep in mind that there is no hard and fast rule about amounts of ferts and frequency of dosing when it comes to EI. The recommendations are just estimates that are for high tech, high light tanks, c02 injected tanks, but it does not mean and I don't believe that Tom Barr has indicated that the frequency of dosing and amounts cannot be tapered down to accomodate low tech tanks. Amounts can be cut to half or frequency reduced from 3 to 2 or even 1 for low tech tanks. The proposed amount and frequency is just an Estimate. 

If you look at Tom Barr's low tech non-c02 tank recommendation and suggestion
http://www.barrreport.com/articles/433-non-co2-methods.htm, I think it can be said that although he talks about dosing ferts one a week, it is the equivalent of dosing one EI "superlean" dose.

I believe that interference with nutrient uptake could impact on plant growth. For instance you may be dosing calcium to compensate for submarginal calcium levels but you may find that plants still display calcium deficiency symptoms eventhough your tank water may test adequate for calcium. In this case it could well be related to a deficiency of magnesium as plants are dependent on adequate magnesium levels for cacium uptake and vica versa. The same may be true for nitrates, your tank water may test more than adequate for nitrate levels but a deficiency elsewhere in the uptake pathway may be interfering with the plants' ability to use the nitrate resulting in what appears as nitrate deficiency symptoms or very poor growth. If I were to speculate or hypothesize, I would say this is what may be going on to explain the stunted plant growth that you are experiencing with PPS-Pro. The mystery to your puzzle may well lie in isolating which particular nutrients may need to be increased, or quite simply set up a control tank and dose EI in that tank for comparison reasons and to make things easier.


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## Left C (Nov 15, 2003)

I got "Page not found" for the Barr link because the ....htm has a , next to it. http://www.barrreport.com/articles/4...o2-methods.htm, I



This one works: http://www.barrreport.com/articles/433-non-co2-methods.html


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## jargonchipmunk (Dec 8, 2008)

Homer_Simpson said:


> still does not explain why java moss on plain gravel in a tank full of guppies would do well unless the fish waste and mulm was providing sufficient nutrients and extra ferts not being necessary.
> 
> I am not trying to bash you, but just trying to understand without the semantic jargon attack.


that actually explains it in and of itself. his setup has been running for years and his java moss has acclimated itself to exactly how many nutrients will be in the water column at any given time to use. High tech tanks can be a sort of roller coaster of nutrient amounts sometimes. (we TRY to have excess all the time so the plants just drink and drink all day long and reach max growth) maybe there are plants that prefer stability over excess. That's what I think I was getting at. There was no attack. I just didn't want anyone reading the forum to get the wrong idea and assume that some plants would rather be in water with no nutrients. I know it seems unfeasible, but we've all seen the posts, "well I read over on this or that forum that java moss likes to be in R/O water with no nutrients" not exactly that, but people blow things like that out of proportion is all. I was merely trying to clarify, not attack. I apologize if it came over that way.


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## Choco (Dec 8, 2007)

Try lowering your lighting if you have problem growing java moss.
I had a small tank with java moss and very strong light. A lot of the moss ends up turning brown for some reason.

Also, a densely population guppy tank will produce nutrients (nitrate) far exceeding your normal dosage of fertilizer.


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## plantbrain (Dec 15, 2003)

imeridian said:


> The dead fish might be a pretty good warning sign before that would happen too. :icon_eek:


This is far more likely and testable before anyone sees any excess dosing issues, particurarly for CO2. I've heard all the critics poo poo on EI and non limiting ppm's for plants, but never have I seen them ever once use a control for comparing what they are seeing and address how others can add say 100 ppm of K+ without issues on the same plant for several months.

How can they explain that away?
They cannot, so they avoid addressing that question and simply are not being honest about things.

I get aggressive and go after such thinking, which often places these blow hards into a corner to defend their ego, but they hung themselves by their own rope:thumbsup:

Here's a simple question: how do you think they grow these aquatic plants we use at the commericial level?

Hydroponically, what do you think the concentrations are in the hydroponic nutrient solutions and what are the limits there? Very very high, and excess becomes an issue when you start seeing salt stress from too much. Blocking might occur as well, but only at very high concentrations and severe imbalances, something that does not ever occur in aquariums. Aquariums are extremely lean by any comparative measure.

But that does not stop people from supporting and making the myth live.
I've resoundly shown for many years that these so called blow hard critics of EI are full of Azolla, first is was algae blooms(strike one), then fish health(strike two), then plant growth aesthetics/stunting etc(strike 3!).

I did this for K+, PO4, NO3, Fe, GH.

What the heck have they done?

Not much...........other than a lot of talk, speculation, grand intentions without any results.

The idea of non limiting nutrients when many aquarist have been conditioned and told that "excess" is bad is a conflict for many. However, there is a difference between "non limiting nutrients" and "excess", quite a large range there in between and when you do not even have a clear understanding of what those concentrations might be, how can you debate someone that does and has tested them?

They still try:icon_eek:

What is "excess"? This is a vague catch all phrase very popular on forums. 
Is it non limiting? I suppose yes in some respects, but the preception between these two are very different.

One sounds bad, dirty, the other sounds reasonable and specific to pant growth.

DaveS, you mentioned this:


> just that the growth is somehow being inhibited.


How do you _know_ that the plants are inhibited and not limited? Other things come into play besides nutrients that can radically limit growth, the largest being light followed quickly by CO2.

Cleaning the tank, plant biomass %, species of plants kept together, fish and waste loading, current etc etc.

This is not all about nutrients.
What you see as excess might very well be a seconardy issue related to limitation in another area you think it the okay, the same, "I have not changed anything" (does not mean it has not changed), and you have a single tank to draw the conclusions from(many folks have several tanks they all trwat the same but have different results- you nee a few reps to make a general conclusion here).

There's also no control. I can take a tank that's doing well and do these same treatments without issue. How can explain that with this theory of inhibition?

For that to be correct, we should see it in all cases or at least 90% etc of them when we do decent good methods. Yet those results are simply not there. I have many species of moss at high levels withut any issue, well..other than the moss becoming really weedy and growing on everything:redface:

So I have to based on logic say I cannot accept that hypothesis, there must be an alternative one we should look for instead. It's not a personal thing, it's just a process to rule one thing out and seek the other more likely reason for the issue.

Maybe it's water changes, maybe it is temperature, maybe it's light, CO2, cleaning the filter more often, there are many ways to fail, but we need a control tank that's doing well to see if we want to test our theory.

A tank that does not have these limitations. Then we can see if there is any inhibiting factors like say excess K+ blocking Ca uptake and not a lack of CO2 that is stunting the tips of the plants. 

BTW, that's not true(excess K+(up to over 100ppm) does not block Ca in plant growth, only as a signalling messenger intercellularly- big difference there). We showed this clearly in several cases.

Thus poor controls/lack of them caused poor conclusions, but many people fell for the poor logic/methods and results/conclusion that where made. Then a bunch of "me too's" ran around claiming they saw the same things.

Ahhh.......now a myth is born/fed to the hobby and I'm a bad guy for saying that these well intentioned and thoughtful people trying to help other hobbyist are "wrong". "How rude! And I still see the results in my tank and can solve it by adding less(limiting) K+!" 

Been here, heard this, done this hundred's of times. 

Rather than trying to solve the specific cases, I go after the real larger question, like what nutrients inhibit others and at what concentrations do they occur at? This is specific, not vague.

Then I can rule out such malarkey in the future from then on.
That's more useful than trying to solve everyone's specific problem and makes that process of problem solving much faster, and simpler:thumbsup:

Some just do not get it though. 


Regards, 
Tom Barr


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## Guest (Jan 7, 2009)

I wonder if there has ever been one post by Tom that never ceases to amaze me. You need a myth busted or facts proven Tom is there. I guess its always nice though to have someone not beat around the bush and call it like he sees it.


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## plantbrain (Dec 15, 2003)

Well new folks cannot be blamed, all we can do is simply learn more and correct things as we learn. Hopefully the next crop of folks helping the new folks out are better able than those before to address things.

We all start out ignorant:thumbsup:
Just don't stay that way:redface:
It can be humbling to fess and say you do not know muh, but do some background work, see what you can learn and when you have conflicts or questions, ask.

That's what this person did, we are really no different.
So have some pity upon them and help out.

Regards, 
Tom Barr


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## Church (Sep 14, 2004)

plantbrain said:


> Well new folks cannot be blamed, all we can do is simply learn more and correct things as we learn. Hopefully the next crop of folks helping the new folks out are better able than those before to address things.


That is one powerful statement right there.


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## DaveS (Mar 2, 2008)

plantbrain said:


> DaveS, you mentioned this:
> 
> 
> How do you _know_ that the plants are inhibited and not limited? Other things come into play besides nutrients that can radically limit growth, the largest being light followed quickly by CO2.
> ...


Thanks for the input Tom, and I can't disagree with your other points here. I would however like to mention that this was not one single tank, but two tanks with fairly similar parameters except for water volume. As I mentioned, one tank was 20g the other was 75g and the dosing regiments as far as nutrients per gallon were identical and the growth results in both tanks were very similar if not identical as well. I have several other tanks on my "old" system of dosing the recommended Flourish once a week and they showed better and more robust growth over the same period of time. All tanks get the same % waterchange weekly, and I pull my change water from a central water source so that isn't a factor.

Both tanks are well established (one is about 12 years along, the other is 11), which maybe explains something as well Perhaps change isn't always a good thing.

I am only trying to explain why changing to a more nutrient rich dosing regiment resulted in noticeably worse growth and healthiness in those two tanks, and going back to a leaner approach resulted in very rapid improvement in both tanks. I have to think that something I was adding, or perhaps something lacking in the PPS Pro regiment but is present in Flourish can be shown to be the cause here. I could care less about new or old myths and I certainly don't want to add to them. I only want to know why what seems to be a more balanced and rich approach failed so completely in these two tanks.

My whole point here was to become less ignorant when it comes to nutrient uptake and the balance needed to achieve robust and healthy growth. I would not have otherwise decided to change my routines in these tanks to see what happens. Obviously something in this approach is not correct and I would like to know what it is.

Dave


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## DaveS (Mar 2, 2008)

Just one other point here and I will let this die. I am an engineer, and by nature I like to tinker with things and see what makes them tick. I can easily go to an EI approach and perhaps that will make things all better in both of these tanks. However, what I really want to know is *why *this particular approach did not work. By simply changing to another approach and getting good results does not give me what I am looking for. I want to gain a little knowledge here as to what is going on in the details of the plant growth in these tanks. Anything else and I will never know where I went wrong, and I will never be able to apply that in the future which is what this is all about. If I need to take a spanking or lecture to get me to that point, so be it. I would however like to have a little science to explain what I have seen over the past year in these two tanks.

Dave


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## Wö£fëñxXx (Dec 2, 2003)

I can't give mathematical equations on which nutrient goes where and why.
I do have some experience so maybe I can help.

These are low light tanks that do not even really need dosing even though
you are using Excel, these type of tanks use little in added nutrients based
on rate of growth, with the absence of pressurized C02 & high light plants
are limited already on how fast they will grow therefore on how much salt
they need.

Fish/plant waste will almost suffice, with the right setup it will, so adding
extra salt in whatever form it may be is abundant, so the plants cannot
use it, so the biological bacteria is trying to process all the excess and
it can't keep up. To much stress on the bio-system.

Without knowing what kind of filters you have/how they are setup and
when they are maintained, or what substrate and how deep also determines
overall stability and resilience.

It appears to me you are polluting the water with an over abundance of
salt and substances which is most likely damaging the bacteria, micro-
organisms and it passes down the line until plants are affected, next
will be the fish/shrimp.

PPS and EI both are usually for a med-high/highlight C02 injected tank,
under highlight excess does not matter so much as long as there is enough
for the plants when they need it.

In low light the eco system maybe stressed on the amount of higher light
nutrients in a low light environment.

I have a couple of low light tanks along with snazzy high tech tanks,
the low light tanks rarely get any added salt/nutrients on my part,
most is delivered via fish food/waste and the eco-system sustaining
itself.

I bet you're TDS was/is through the roof.

Now try your test with few nutrients other than fish/food/waste.
Add a little K+ and TE once a week or so, does not take much.
You could get away without having to add those at all.


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## plantbrain (Dec 15, 2003)

DaveS said:


> Thanks for the input Tom, and I can't disagree with your other points here. I would however like to mention that this was not one single tank, but two tanks with fairly similar parameters except for water volume. As I mentioned, one tank was 20g the other was 75g and the dosing regiments as far as nutrients per gallon were identical and the growth results in both tanks were very similar if not identical as well. I have several other tanks on my "old" system of dosing the recommended Flourish once a week and they showed better and more robust growth over the same period of time. All tanks get the same % waterchange weekly, and I pull my change water from a central water source so that isn't a factor.


Are any two wetlands the same then as well?
Unless you run a control, you cannot compare these tanks. 
You must have something to compare it to.
Some standard known situation at least and then manipulate.
Otherwise you have not confirmed what it is that you are seeing and why is correc or not.

We need to be sure, not just "wing it" and pray for the best. 
Sometimes that's all we got, so folks often go with it.

But if someone does the work and background research, finds no evidence that this specific issue causes these effects, then............and it's well suported in research test cases also? I have trouble with that, sorry, nothing personal here :redface:



> Both tanks are well established (one is about 12 years along, the other is 11), which maybe explains something as well Perhaps change isn't always a good thing.


Well, the tanks have changed a lot, and what we, the humans that we are, allow the systems to sit, or perhaps we tend them a lot, I can assure you my mainteanace is different than Amano's or yours. Some are aggressive gardeners, others allow the tank to sit. Some do more water changes and scaping than others, some add enough CO2, some do not.

Your habits and routines for those years might have a lot to do with it in other words. 



> I am only trying to explain why changing to a more nutrient rich dosing regiment resulted in noticeably worse growth and healthiness in those two tanks, and going back to a leaner approach resulted in very rapid improvement in both tanks.


So if you do not assume that it is due to the "lesser is better" claims. which smacks in the face of hydroponics and farming etc........why else might those horticultural methods work well with more whereas submersed growth might not?

What else are we not talking about here?
CO2 and light.
Light is fairly stable, but you might have a little or lot and that will influence CO2 a great deal.

Why might some folks think low, less PO4 = less algae whereas I cn add 4 -5ppm every week without any algae issues at all(ADA level or higher)?

What happens to CO2 demand if you limit nutrients strongly?
It goes way down.

So if you had not been adding it well to start with, or the delivery system adding CO2 was poor and could not keep up, limiting nutrients would reduce that and make the CO2 issue go away by reducing the demand.

Less light would also do the same thing. 

This model explains why limiting nutrients can get rid of algae, but not for the direct effects that many aquarist like to speculate and assuem that they do.
Only by testing the indirect effects and setting up a simply control where we do not have issues at high nutrients nor CO2, do we see the real picture of what is going on there.

Do not assume that the effects are direct:thumbsup:
Many are indirect and the root cause for most algae issues, and this is testable and repeatable, is CO2, about 95%.

The same logic you are using is what Paul Sears and others had speculated with PO4 about algae and nutrients. But.........it was falsified by testing that hypothesis, same deal here.

You might not see it because you are not addressing those indirect effects of say CO2.

This is understandable. But.........you cannot explain why I do not have any such issues when I do this same thing at much higher nutrients levels with the most sensitive persnickety of plants:










Why are these plants not stuntred or harmed by rich sediment and rich water column nutrients?

The hypothesis you made has been tested(and tested many many times already for decades now).

So you have to reject such models and find an alternative model, one that can explain the observations. My model does address it and has a fair amount of support and logic behind it. We can test limiting nutrients and watch CO2 demand go way way down, there's research support for that linkage all the way to the whole plant level down to the Genomic level.

We can induce various species of algae by reducing CO2. We can get rid of many species by raising the CO2 and improving mixing and/flow filtration. 

We can reduce the light and slow the growth rates, which in turn suggets like Carbon demand is required, this can be measured as well.



> I have to think that something I was adding, or perhaps something lacking in the PPS Pro regiment but is present in Flourish can be shown to be the cause here.


Rather than thinking about adding too much, you should also turn over that other stone...........what might you be limiting and what might have been midly limiting prior?

What might be limiting plant growth beside nutrients and what might adding non limiting nutrients do to the other parameters like light and CO2?

If you want to get the most efficency out of the system(eg, the best growth rates and the least algae), how might you go about that?

Moderate to low light=> easier to manage CO2 and growth rates of the plants => good ample CO2=> less algae, more stbale growth => non limiting nutrients.

If you limit nutients, that reduces CO2 demand in the plants.
Likwise if you limit/reduce light, you also reduce CO2 demand in plants.



> I could care less about new or old myths and I certainly don't want to add to them. I only want to know why what seems to be a more balanced and rich approach failed so completely in these two tanks.


Ask yourself why other folks can do it without issues. Are we lying in a great conspiracy? hehe
Not likely huh?

This is not a simple 2 box model here. We have other indirect effects, one thing influences another that can cuase the effect we observe.

Adding more CO2 to a strongly PO4 limited tank will not yield any effect.
Adding more CO2 to a CO2 limited tank will.............
Is the uptake of CO2 higher or lower with non limiting nutrients?
Higher.

This is a holistic view, taking all the parameters of growth into account, not a simple 2 box model.

Then testing them to see which is the root cause of the issue.
Nutrient limitations are extremely easy for me and anyone really, to rule out as cause. Large % water change and add the ferts back right after. The tank is basically a reference solution at that point.

Then a PAR light meter etc, or use a known light standard, and all you are left with is CO2.

Cleaning the filter, pruning and other factors are certainly present but we assuem folks have a good consistent routine and know the basics of fish aquarium keeping prior(still, folks often over look that, what is fully planted tank etc).



> My whole point here was to become less ignorant when it comes to nutrient uptake and the balance needed to achieve robust and healthy growth.


Me too:redface:
I am really quite ignorant about a great many things.
Which is why I have to test and confirm to know what little that I do.

[/quote]
I would not have otherwise decided to change my routines in these tanks to see what happens. Obviously something in this approach is not correct and I would like to know what it is.

Dave[/QUOTE]

It likely has nothing to do with the nutrients which is what I mentioned and suggested using methods, test and results. The nutrients caused indirect results that you saw. Your eyes did not lie, your brain led you off the path:redface:

There's a saying " do not believe everything you think".
Many do.

I question my beliefs and brain, it's been wrong before:thumbsup:

I'd focus heavily on CO2. Clean and prep the tank well, clean filter, trim things up, do many water changes, then try EI and make sure the CO2 is good. You should see dramatic growth. You might consider more water changes, say 2x a week 50% for the first 1-2 weeks, but tweaking the CO2 is the real goal there.

That is not something most folks can nail on day 1.
It's an eye ball thing for most.

You might not wanna bother after seeing the rapid growth, or you could swap out different plants that are not so weedy under non limiting conditions.

So in that case, you might try less light intensity. That will make CO2 easier, and nutrients.

So you have a few options and now know how to control the rates of growth without algae issues or poor growth, to suit your goal and routines.

I simply zip the light up and down on my wire suspensions to adjust for a vacation, or if I want to garden more, I lower it for more light intensity.

I can still dose the same CO2 and nutrients if I want, but need less for the lower light. I have my lazy days and my work days:redface:
We all do.

Regards, 
Tom Barr

Regards, 
Tom Barr


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## DaveS (Mar 2, 2008)

Thank you very much Tom, that gives me quite a bit to think about.

I have already addressed what I believed to be one major issue on the 75g tank by adding a fully pressurized CO2 system. I haven't moved over to the EI system yet as I was under the impression that my light levels might be too low for it, but perhaps I can give it a try and see what happens. 

Dave


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## plantbrain (Dec 15, 2003)

DaveS said:


> Just one other point here and I will let this die. I am an engineer, and by nature I like to tinker with things and see what makes them tick. I can easily go to an EI approach and perhaps that will make things all better in both of these tanks. However, what I really want to know is *why *this particular approach did not work. By simply changing to another approach and getting good results does not give me what I am looking for. I want to gain a little knowledge here as to what is going on in the details of the plant growth in these tanks. Anything else and I will never know where I went wrong, and I will never be able to apply that in the future which is what this is all about. If I need to take a spanking or lecture to get me to that point, so be it. I would however like to have a little science to explain what I have seen over the past year in these two tanks.
> 
> Dave


I dount the results will be any different with EI.
The real issue is more to do with the light and CO2.
Nutrients by and large are easy.

Engineers can go either way, some dolts when it comes to Biological systems, some are not, there's a so called divide there, but I started out as engineer and then went to Biology. Still, they oftren over look things an of course Biologist often do the same in egineering also.

Working together is the best solution but not always set up that way in the bureaucracy:thumbsup:

Regards, 
Tom Barr


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## plantbrain (Dec 15, 2003)

DaveS said:


> Thank you very much Tom, that gives me quite a bit to think about.
> 
> I have already addressed what I believed to be one major issue on the 75g tank by adding a fully pressurized CO2 system. I haven't moved over to the EI system yet as I was under the impression that my light levels might be too low for it, but perhaps I can give it a try and see what happens.
> 
> Dave


Don't till you get real friendly with the CO2 and it's effects on fish and critters, as well as plants. No rush. Learn and focus on CO2 more than anything. That is where it is at, nutrients are really easy... truth be told. 

Regards, 
Tom Barr


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## pthalobluebetta (Jul 24, 2008)

I thought I'd add that I find java moss growing like a weed in my 2.5 gallon tank. It's got red flourite as the substrate (got that from a friend), a small piece of driftwood, and 3 baby platies measuring about 1/2 an inch long. a few small snails, and a 12 watt cfl light, that's placed right on top of the glass cover. And red sea nano HOB filter. I don't dose the tank with anything, feed the finish once a day with a generous pinch of micropellets, and haven't changed the water in maybe 6 or 10 months, ever since my betta died of old age in there. Rotala rotifundala grows really slowly in there, Riccia (floated) dies, the whole thing was overgrown with vals until about a month ago when it all went transparent yellow and died at once - I suspect it used up all the nutrients. Nessea grows okay in there, slow. Mostly the tank is just 75% green and healthy java moss, which I had to trim back when it reached 1" from the light because then the top just became a hair algae farm. The 2.5g mostly serves as my extra trimmings tank, but I'm planning to rescape it this month for a new betta. 

Then there's my 6gal nano cube, 18w CFL, about a 20% water change every 3 or 4 months. Currently just baby sits my 4 platies, 3 amano shrimp, and a few snails. AS amazonia substrate over 2 yrs old. Dosed regularly with 1/2 cap of Excel daily and 1ml to 1/2 of Flourish weekly. Feed micropellets once a day. Nesea grows as a super healthy weed in here, as does my Val and Rotala. I think I have Wendii which grows so slow you wouldn't believe it was actually spreading. I moved out the java moss but it didn't due too well in here due to the rotala and nesea covering the top of the tank. 

Then there's my 30g.. co2, ferts, the works... still trying to figure it out.. I think the increased plant mass has changed things and is requiring more co2 than before, and some recent feeding changes might require leaner ferts.


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