# What would cause GDA on a fast growing plant leaf???



## Seattle_Aquarist (Jun 15, 2008)

Hi bsmith782,

My GDA seemed to be caused by low NO3. I used the Method of Controlled Imbalances (MCI) and have almost fully eliminated my GDA. It involves increasing KNO3 until GDA is eliminated and replaced by GSA, then increasing PO4 to eliminate the GSA. It took a several weeks, and I ended up increasing my KNO3 dosage by more than 3X EI dosage, but it worked and my GDA is gone. (FYI, even with the higher KNO3 dosage, I found that my NO3 levels were about 5ppm after 24 hours.) I am in "phase 2" where I am increasing my dosage of PO4 to eliminate a small amount of GSA I am currently getting. You may want to give the procedure a try.


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## plantbrain (Dec 15, 2003)

At 3x EI, there's no way the NO3 could be 5ppm.............
This would imply uptake rates of 15ppm or more per day of NO3...........

Try less light.

Will do the same thing, more available N, P, CO2 etc.
That, and stable CO2. Then once the plants are doing well and algae, free, back up to the old light intensity.

The only times I've ever had GDA was when the CO2 was low. I have 5 tanks, all get the SAME dosing, same sediment in 3 tanks(ADA AS) one with Flourite and then Dolomite in one. Light is about the same also, maybe off by 10-20micmols depending. So nutrients are the same, the sediment is not a factor, the light is not either.
I could not induce GDA for the life of me in the other tanks.

Without consistent induction of algae at the blooming stage, you cannot test anything for algae.
That is standard protocol for algae test in research.

Just 2 and the only the one's with poor CO2.
When the CO2 was tweaked and fixed, the issue went away in both tanks at the same time.
I cannot say 100% that was it. But I know it's not a nutrient or sediment type issue, tap water, water change etc.

Those had no impact and yet the algae went away and has done so consistently.
I'm not saying mega dosing nutrients or KNO3, or dropping PO4 down is going to do anything or not, only that it cannot be the cause or the only reason.
I think someone is implying that to be the case.

I have not seen evidence that demonstrates that nutrients are the cause of the problem to begin with.
No one also seems to be able to consistently induce GDA either.

I have fairly low intensity now, that was changed in one tank, but not the other. That seemed to reduce it.
But CO2 seems to be the largest factor, the aquariums both had wet/drys, but I've had it in high light canister filter tanks also, but again, in that tank, CO2 was it.
Nothing wrong with mega dosing nutrients. I suggested this for competitions and doing them the day prior to a water change to fatten plants up.

If you try and change the ppm's of NO3 or PO4 around etc, you are bound to get some effect I figure.
Does not hurt to try.

But it still does not imply cause, or that there is another factor that is influence, eg, limiting one nutrient STRONGLY influences CO2 etc......since CO2 is not tested independently, you cannot say if it's the nutrients limiting CO2 demand, or the nutrients themselves causing the effect.

Algae are rarely limited, plants virtually always are to some degree.
Limiting PO4 was very popular, and plants can handle PO4 limitation fairly well, so you will still get growth, but reduced CO2 demand, this is why many assumed PO4 excess = BBA.
However, I have crazy imbalances and no such issues. In order for the theory to hold true, you must test the other side of the coin there to make sure it was not CO2, rather than limiting PO4 or NO3, or Fe etc.

Indirect effects are one reason why correlation does not imply cause.
This was true back when PMDD came out.
They stated similar things about algae, but much less ppm's.


Regards, 
Tom Barr






Regards, 
Tom Barr


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## plantbrain (Dec 15, 2003)

Seattle_Aquarist said:


> Hi bsmith782,
> 
> My GSA seemed to be caused by low NO3. I used the Method of Controlled Imbalances (MCI) and have almost fully eliminated my GDA. It involves increasing KNO3 until GDA is eliminated and replaced by GSA, then increasing PO4 to eliminate the GSA. It took a several weeks, and I ended up increasing my KNO3 dosage by more than 3X EI dosage, but it worked and my GDA is gone. (FYI, even with the higher KNO3 dosage, I found that my NO3 levels were about 5ppm after 24 hours.) I am in "phase 2" where I am increasing my dosage of PO4 to eliminate a small amount of GSA I am currently getting. You may want to give the procedure a try.


Is this due to PO4 or that the PO4 limitation reduced CO2 demand, thereby curing the issue?

In otherwords, how can you(or anyone) be certain that it's not due to CO2 demand rather than PO4 limitiation for a few weeks?

This was the same error made with PMDD, it also eliminated algae the same indirect way, but claimed it was from nutrient management, which can certainly reduce or increase CO2 demand depending on what you add.

However, this method, as well as PMDD also did not look at the alternatives and see why algae did not flourish in high PO4 aquariums(like my own) and where I have no GDA even after inoculating it.

The only changes I made where CO2 related, the NO3 was 20ppm and the PO4 was 5ppm.

I only had GDA in the poor CO2 aquariums and tried hard to get it to grow in other tanks where the CO2 was optimal.

So how can that theory explain both observations(facts)?
It cannot.

There might be the same thing occurring(CO2 demand reduction) and the reduction of the light intensity also does a similar effect and cures many types of algae as well.
This would explain both observations(facts), the other nutrient idea does not however.

So........we know limiting nutrients have effects on CO2 and light demand, likewise, we know that less light = less CO2= less nutrient demand.

This theory works much better and explains far more than playing with/manipulating nutrients alone, and is why you want to look at the broader picture and make sure you do not over look something.
Some method might work, but not for the reasons you think it does:icon_idea

PMDD made this assumption, however, it could never explain why I had no algae with high PO4, nor can this with my tanks and 5 ppm of PO4 and high NO3.
It might still work for GDA or other species, then resets things, nothing wrong with that method I think.........but why it works is falsifiable (if you assume that limiting PO4/Ca/PO4 balances play some role)based on the observations. It might be that 2 things cause/induce, but I find that very unlikely, I shoud still have GDA, however, with several aquariums and only 2 with the poor CO2.......and then 2 client's tanks.......it is pretty clear, it's not just PO4/Ca.





Regards, 
Tom Barr


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## bsmith (Jan 8, 2007)

In my tanks the only algea that I would say coincide with low/fluctuating co2 is bba at the light levels I have. The only fluctuations I have is that (according to my drop checker 2cm off the substrate in the lowest flow area of the tank) co2 seems slightly low for a few hours after the lights go on. But this could also be the fact that drop checkers are a slow reacting indicator of co2 levels. I had BBA a bit after I got back from vacation and the tank water was down about 4" and the splashing caused levels do get low even during normal full saturation times. 

Believe me I am about the biggest proponent of low/fluctuating co2 causing just about EVERY algea issue. It has been consistently good (back from vacation) for about a month.

So you think I should just wait it out?



plantbrain said:


> At 3x EI, there's no way the NO3 could be 5ppm.............
> This would imply uptake rates of 15ppm or more per day of NO3...........
> 
> Try less light.
> ...


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## plantbrain (Dec 15, 2003)

bsmith782 said:


> In my tanks the only algea that I would say coincide with low/fluctuating co2 is bba at the light levels I have. The only fluctuations I have is that (according to my drop checker 2cm off the substrate in the lowest flow area of the tank) co2 seems slightly low for a few hours after the lights go on. But this could also be the fact that drop checkers are a slow reacting indicator of co2 levels. I had BBA a bit after I got back from vacation and the tank water was down about 4" and the splashing caused levels do get low even during normal full saturation times.
> 
> Believe me I am about the biggest proponent of low/fluctuating co2 causing just about EVERY algea issue. It has been consistently good (back from vacation) for about a month.
> 
> So you think I should just wait it out?


I've observed a lot of tanks with CO2 issues over the years.
In general, I try and correct it before there;'s a plant issue, the next stage is an algae issue, sometimes you do not see a plant issue, it goes right to algae.

But with time, and simply being patient, good CO2 will stop new growth, the slowly dying algae(adults, not the new spore germinated young algae) will drop off after a week, 2-3-4 weeks etc, and I trim a little here and there etc.

In other words, I do not try and make a huge trim and larger changes once the CO2 is good. As long as the algae is slowly retreating, I know I got it licked.

So I can afford to take my time. As the plants recover, they grow faster and faster. So now I can trim more, maybe add Excel, maybe do water changes 2x a week until things are better etc.

With green algae, I've recently tried a few different things that work well, multiple cycles of 3 days on/off of lighting blackouts.

Not just one cycle(3 days off, then back on), but 3-4 in a row( 3days off, 3 days on, 3 days off, 3 days on etc).

This is highly effective against the green hair algae.
Both Cladophora and Spirogyra and most any others.........

BBA and red algae are pretty easy, annoying, but easy to get rid of with CO2 alone. Good CO2 will prevent new infestations of green algae, but often once there, the greens are tougher to get rid of.

If you think about plants, algae as a whole, the growth for each starts with light, then CO2 is next.............

The mob mind set tends to forget this and likes to blame nutrients for everything.

I keep algae control separate from plant horticulture.
This is wise because it's a different focus and goal than plant growth alone.
We all know, and this is universal...that good plant growth and health means no algae growth to speak of.

So focusing on that, not algae is always the focus.

If you growing algae and inducing it to learn more about how is behaves in planted systems is the goal, that is a very different approach. Many try and fuse nutrients and algae control together. This typically has a lot of flaws.

PMDD had this issue, but it was indirect for the success, the better nutrient management = better plant growth, not ....limiting algae. That part of the hypothesis was a non tested assumption.

Others have tried to do this since, again, unable to explain why I have high PO4, NO3, Fe, all sorts of "ratios" etc for any number of nutrients they speculate.....but I can control algae easily, and every algae species.......... without having to limit, change or alter a single nutrient.

All dosing methods have examples of good algae blooms and issues/problem cases. All dosing methods also have good examples of success.

It seems rather obvious that it's not just dosing nutrients that is some sort of key factor there, it's the light and the CO2, which play larger roles and if you really think about it............is just plain common sense. 

That is how plants grow.

Light and CO2 come first, not nutrients.
Light drives the plant's enzymes to be able to take up CO2 and reduce it to sugars. From there, they need N, P, etc.........

Liebig's law applies. If you never test for independence for nutrients, you cannot say anything about CO2 or light. If you never test for PAR in the aquarium to compare, then light is not tested either.

You just cannot say much without having tested the various parameters well.
Many seem to think they can without doing the work and testing both sides of the coin.

You can say there is correlation(and the method might work well limiting nutrients for a time etc and controlling algae), you cannot say anything about cause/why, you might speculate, but that's about it. If you test the CO2 independently of nutrients, then you can say a lot more.

Observations show that algae and issues can be changed with nutrients, but also, and perhaps much more dramatically for every dosing method, even more so with CO2(increasing it), and also light changes(reduction typically which provides more CO2 by reducing demand and more available nutrients)

I've seen the GDa on fast growing plant leaves.
I had the algae and several tanks, 2 had it, 3 did not. I inoculated all the tanks, each had the same light type and intensity(easy to adjust for this with suspension lighting all the same brand and bulb types and a PAR meter)
Only 2 aquariums had issues with GDA, one was rather persistent.
The other went away pretty fast after taping the wet dry up to reduce leaking of CO2.
The other tank had issues with CO2 as well, which took longer to correct, while plants grew, now after correcting the CO2, they all grow much much better and are much healthier.

Curiously, the GDA went away without a single change to the nutrient dosing.
Sediment type was also different and similar for the affected and non affected aquariums.

If you only had 1 maybe 2 aquariums, you could not say that much.
Most folks typically have only 1-2 planted tanks. So not nearly as powerful for comparisons if you have 5 or more with similar set ups(client tanks are also very helpful to me).

There really is very little known about CO2 enrichment, measurement etc in planted aquariums. Same for light.


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## bsmith (Jan 8, 2007)

I am just going to have to reduce my photo period then. I don't believe I can cram any more co2 into the tank and really measure it safely. My drop checker is yellow but fish are acting normal and there is no noticeable discomfort or respiration issues so there may be a little room. Maybe I need a 5dkh solution instead of 4? There is still gda on my limno aromatica that has just grown and as stated before co2 has been consistent for a month or so.


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## bsmith (Jan 8, 2007)

I just reduced my photo period to 6.5 hours, seem too short too me. I also just ordered all new NPK and csm-b because I cannot entirely rule out that I may have switched/combined my old nutrients attempting to combine old and new ferts. This was always a thought


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