# How does high plant bio-load help reduce potential for algae?



## onlycrimson (Sep 7, 2010)

They will pull nutrients from the water making them unavailable to algae. Basically when you have a lot of plants they outcompete most algae for food.


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## Hoppy (Dec 24, 2005)

Algae and plants are not in competition for food. Algae require such minute amounts of food there is always plenty in the water for them, whether you have lots of fast growing plants or none. Algae are inhibited from starting to grow when there are lots of healthy, growing plants in the tank. The exact reason for this doesn't seem to be fully known. But, it is probably the chemicals released by dying or unhealthy plants that trigger algae spores to start to grow.


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## isonychia (Nov 19, 2013)

If it's nutrients that are being removed, then I would speculate that an excess of nutrients is one cause of algae, thus why a high bio-load is suggested.

So what constitutes "nutrients"?

iso


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## isonychia (Nov 19, 2013)

Ok, so what Hoppy suggested is the missing piece I couldn't understand.

Although, as he suggested it seems it's not exactly clear what a high HEALTHY bioload is doing to reduce the chances of algae, only that a low unhealthy bioload is a risk factor for algae.

I am currently doing frequent water changes etc to try and combat the algae problem.

I didn't understand what a high plant bioload was actually doing that was different than me doing frequent water changes to reduce X.

I was reading how excessive dosing, high nitrates, phosphates, etc etc was not thought to be the cause of algae but possibly closer linked to the low bioload of plants and CO2 and lighting amounts.

I think the main thing I missed in all this is, if you want to keep plants that require filling in to establish themselves and multiply, GET SOME OTHER PLANTS that substitue for a healthy bio load until the plants you want to keep catch up. Then donate or start another tank with the substitute plants.

So the MM, Monte Carlo, Fissidens Fontanus that I chose are very small in the bio load dept to make a dent.

The other plants I have, anubias nana petite and star grass are better choices, but still not enough to reach the level of bio-load needed to reduce the possibility of algae growth.

Does that sound about right?

iso


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## Okedokey (Sep 2, 2014)

Yes, I agree with Hoppy. If it were the removal of nutrients, we wouldn't use EI.

I believe it is allelopathy and other hormones and that the prevention of decaying matter (due to healthy plants) from being created reduces or eliminates algae.


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## evaninspace (Feb 19, 2014)

Okedokey said:


> Yes, I agree with Hoppy. If it were the removal of nutrients, we wouldn't use EI.


On that point...reading Barr's comments on using KNO3 to reduce BGA it seemed to me that there is a link.

Using my personal experience as an example. Dosing normal ei calculated for my 55g I had a plan using KNO3, KH2PO4 & CSM+b. Tons of large plants, fast growers, slow growers..the whole mix. I was getting BGA everywhere on the substrate. The way I read Barr's comments, the plants were limited in their use of KH2PO4 + CSMB because they had used up the KNO3 resources. The algae would then thrive on the remaining dosed nutriets. Soon as I started upping the KNO3 above the EI calc recommended dose, the BGA vanished within a couple of days. I have not stopped the extra KNO3 dosing and have had zero issues with algae or the livestock. 

To me it seemed the KNO3 was the limiting factor. Up the KNO3 and the plants consume that, and subsequently the remaining nutrients as they grow accordingly.

On my way out of the office and wrote this up rather hastily. Hope it made sense/was relevant


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## onlycrimson (Sep 7, 2010)

I apologize for my bad info then. Coming from the reef hobby and Koi Hobby it seemed that excess nutrient in the water was one cause of algae. 

If I removed all my plants and kept on dosing EI as I had been my presumption would be lots of algae growth because it now has a lot of nutrient available, is that not the case? I was under the assumption that by having lots of plants that rapidly take in nutrient that I was limiting what the algae could use. I know there will always be nutrients available, I just thought less would mean less algae.


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## BBradbury (Nov 8, 2010)

*Your Planted Tank*

Hello iso...

I keep a lot of floating plants in my planted tanks. Floaters take in nutrients through the leaves and when these types of plants get large enough, they use more than plants that must go into the bottom material. Anacharis (Common Water Weed) also gives off a mild chemical that's not tolerated by most forms of algae. I take advantage of this, so I have little algae in my tanks. 

B


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## isonychia (Nov 19, 2013)

So, if I add the floaters, won't they block out the light?

Also, when you say floaters, are we talking about things like frogbit or things like watersprite, Anacharis and hornwort?

If I add things like hornwort, do I let it float or use those anchors to let it sit on the bottom without burying it?

Is frogbit a good floater for this? I heard duckweed can become a nuisance. Any others? Water spangles? I just want some suggestions before I venture out to my LFS.

Thanks guys,
iso


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## imcmaster (Jan 30, 2015)

The OP still has an outstanding question ... he wants to build up his plant mass because it is commonly accepted that a large biomass at the beginning helps restrict algae.
This concept is also supported by Tropica:
http://tropica.com/en/guide/get-the-right-start/supporting-plants/
(they say because these fast growers absorb from the water column).

Listed there are several plants that are early and successful growers.

This thread is not going to figure out why a healthy aquarium prevents algae from growing, but like others it is our nature to try to figure out why.

At least two posters have suggested that a healthy plant may leach something into the water that prohibits the growth of algae. I find a few things interesting about this:
1) It supports why a large early biomass helps (lots of leaching?) ... or is it because these plants remove something from the water, and maybe something beyond the obvious nutrients we expect promote growth.
2) If this were so, you might expect a magic bottle of 'algae prevention' to hit the market; none so far ...
3) From an evolutionary perspective, algae came first. A plant evolved something to succeed in the same competitive environment for light/CO2/nutrients, and has 'won'. Could that be the leached compound?

Another poster suggested that BGA removal was assisted by dosing more Nitrates (and that this allowed the plant to uptake the remaining nutrients). Following our hypothesis, the explanation for success is that Nitrates were limiting and the plant was not 'healthy', but removing the limitation (dosing Nitrates) allowed the plant to return to full metabolism and become 'healthy' again (and not that the healthy plants absorbed all remaining nutrients in effect out competing the algae).

Coming back to hoppy's thoughts - maybe it is not the 'healthy leaching', but rather what happens when a plant is suffering in some way. Do the plants leach something then to trigger growth? It does make sense and is consistent with algae growing when a plant is unhealthy, but doesn't explain why an early biomass helps (if it indeed does), or why from an evolutionary perspective algae thrived well before plants.

We know healthy plants leach a % of matter each day (according to Tom Barr - he says 10%). Could it be that algae detect a change in this leaching rate for an unhealthy plant that now leaches less? What other gradients exist that change when a plant stops metabolizing at full rate (that might be detected by algae spores).

Finally, if the leaching of either a 'positive' or 'negative' signal has an effect, wouldn't a large water change effect the concentrations? If a large w/c change helps reduce algae, to me this supports diluting a 'unhealthy plant signal'.

I'd be interested if anyone has any further thoughts. Or tell me that this discussion is fruitless and move on! The search for knowledge is a curse sometimes.


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## isonychia (Nov 19, 2013)

Thanks IMC. I am going to add some frogbit to the tank and some larger floaters like water wisteria/hornwort.

I think my only problem with the large bio-load idea is what exactly constitutes that AND does CO2 injection negate a need for a high bio-load to prevent algae while waiting for the tank to FILL IN?

I ask that, because in my research for varied things planted, I quite often came across aquascape videos like this: https://www.youtube.com/watch?v=Uv0x42x-r7Y
If I had to compare the beginning of that tanks bioload vs mine, I would say they are very close. If I omit the fact that the person is a professional and I am not, why else does that tank GROW IN and not have any algae issues where mine cannot grow in without algae issues? I can only assume one factor is CO2 injection, since my reading about algae mostly said it's either light, CO2, or plant bioload and health, that are the main culprits.

OR is that tank able to sustain itself (algae free) without a large bioload because WITH CO2 the plants grow fast enough and healthy enough to negate the need for a large bioload?

iso


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## imcmaster (Jan 30, 2015)

Great questions! My guess is you must not have any 'limiting' 'factors in the tank. What CO2 levels are required by YOUR plants, based on the amount of light they are receiving, placement in the tank, etc?

iso - how would you describe your light intensity - is it 'low tech'?


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## Kathyy (Feb 22, 2010)

isonychia said:


> Thanks IMC. I am going to add some frogbit to the tank and some larger floaters like water wisteria/hornwort.
> 
> I think my only problem with the large bio-load idea is what exactly constitutes that AND does CO2 injection negate a need for a high bio-load to prevent algae while waiting for the tank to FILL IN?
> 
> ...


The pros don't sit back and admire the newly set up tank. They fluff and change water and wipe down and put in precise amounts of nutrients and nip constantly when a tank is new. See this thread for some insight. http://www.plantedtank.net/forums/showthread.php?t=155525


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## isonychia (Nov 19, 2013)

IMC, I don't know what kind of CO2 levels my plants require. I chose them based on their ability (reported) to flourish in a low tech environment (without CO2).

Here's my plant list:
Anubias Nana Petite
Micranthemum 'Monte Carlo'
Fissidens Fontanus
Marsilea Minuta
Heteranthera Zosterifolia

According to the research I did my PAR should be about 27/30. I have a dimmable LED by SAT. Everything I read said dimming it to 30(value on programmer) is in fact a par of 30 etc.

Last night I reduced my photo period from 10 hours to 8. 
So it is currently set to:
ON: 1pm
OFF: 9pm

The tank gets little to no light from windows, just natural room light that filters in.
iso


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## THE V (Nov 17, 2011)

Good discussion on this topic. It's natural that we try to find a simple answer to this question. The problem is the algae/plant relationship in our tank depends upon the ever-changing status of the little ecosystem we encourage to develop.

Ecosystems are complex and interdependent. In a new tank, they are rapidly changing as new organisms colonize the tank. Even when everything is established there will still be the normal fluctuations due to predator/prey type of relationships.

Stocking plants heavy at the beginning could work because of many reasons. We probably will never know all of them. A few could be shading, alleopathy, nutrient sequestering, or microscopic flora and fauna introduction. 

Sometimes you can do everything right and still get algae outbreaks. I recommend a stocking with a bunch of good algae eaters. My pond snails and BN plecos seem to be doing the trick.


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## imcmaster (Jan 30, 2015)

isonychia said:


> IMC, I don't know what kind of CO2 levels my plants require. I chose them based on their ability (reported) to flourish in a low tech environment (without CO2).
> 
> Here's my plant list:
> Anubias Nana Petite
> ...


The Tropica site lists these plants, and attempts to categorize each of them into low/medium/high in terms of both light and CO2. Three of your plants are listed as 'medium CO2' - which translates to a CO2 ppm of 6-14.
This would suggest you don't have enough CO2 for (MC, Fissidens & Heteranther).
This topic has gone a few different ways now... so I'm not sure if we (collectively) have helped you out.... lol...


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## BruceF (Aug 5, 2011)

How new is this tank? What you are describing is pretty typical of non co2 tanks. The thing about heavily planted tanks is that they correct a lot of problems simply by means of mass. There is plenty of surface area for bacteria to colonize. There is lots of demand for nutrients. Light is filtered and scattered so it is not as intense. Just as V is suggesting. 


I tend to think the vast majority of problems in the early stages of a tank like this are bacterial in nature. I find they always have algae problems and really you just need to let it run its course and keep removing as much as you can until everything stabilizes a bit.


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## onlycrimson (Sep 7, 2010)

Just did a quick google scholar search for articles on this. Found one from 1949 that I'll put a pic in for. Seems interesting but I'm not sure what was concluded because id have to buy the article. But if anyone has access through a Uni it would be an interesting read.


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## isonychia (Nov 19, 2013)

IMC, I did a lot of research on the plants before purchasing.

The problem seemed to be just what you reported. Some people have success with X plant in low tech set ups and others have not. Some research (sites) show X plant is easy and performs well in low tech, others show it as borderline etc.

I felt like (based on research and not personal experience) the only plant that I may have trouble with was the Micranthemum 'Monte Carlo'. I planted this last as an experiment.

Before the brown diatom outbreak and green hair algae, all the plants were doing very well and showing growth. I didn't think the Marsilea Minuta was going to work out, but I put in a small clump of some I received that was very dark and half dead and it started sprouting new growth in about 3 weeks.

The anubias and FF were slow growers so I didn't see much out of them.

The Heteranthera Zosterifolia really took off and was doing well.

Even though the Micranthemum 'Monte Carlo' I planted is covered in brown diatoms, there is new growth that is bright green. I guess the diatoms have not settled on the new growth yet.

How can one measure the CO2 ppm in a non-CO2 tank?


iso



imcmaster said:


> The Tropica site lists these plants, and attempts to categorize each of them into low/medium/high in terms of both light and CO2. Three of your plants are listed as 'medium CO2' - which translates to a CO2 ppm of 6-14.
> This would suggest you don't have enough CO2 for (MC, Fissidens & Heteranther).
> This topic has gone a few different ways now... so I'm not sure if we (collectively) have helped you out.... lol...


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## Hoppy (Dec 24, 2005)

imcmaster said:


> The OP still has an outstanding question ... he wants to build up his plant mass because it is commonly accepted that a large biomass at the beginning helps restrict algae.
> This concept is also supported by Tropica:
> http://tropica.com/en/guide/get-the-right-start/supporting-plants/
> (they say because these fast growers absorb from the water column).
> ...


If either allelopathic chemicals or "poor health leaching" were involved with algae we should be able to either cause or stop algae by using a big activated charcoal filter to remove those chemicals before they reach a concentration that makes them do their magic. That doesn't seem to be an effect that anyone has noted with use of activated charcoal filters. So, I think we may be back where we started.


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## jeffkrol (Jun 5, 2013)

Hoppy said:


> If either allelopathic chemicals or "poor health leaching" were involved with algae we should be able to either cause or stop algae by using a big activated charcoal filter to remove those chemicals before they reach a concentration that makes them do their magic. That doesn't seem to be an effect that anyone has noted with use of activated charcoal filters. So, I think we may be back where we started.


There is more than one kind of algea and they behave differently.. i.e macro algae and micro algae, and blue-green algae.. 
There are limited studies describing both allleopathic chemicals produced by higher plants, filamentous algae, single cell algae, and even bacteria living off plant "debris"..and Nitrogen limitations in the water column favoring higher rooted plants.
These have been shown to inhibit each other i.e even some plants inhibit other plants.. ect.
Complicated mess..
Knock yourself out 
http://jlakes.org/web/Allelopathy_aquatic-autotrophs-CRPS2003.pdf


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## isonychia (Nov 19, 2013)

There are a lot of posts and great information, thanks guys.



BruceF said:


> How new is this tank? What you are describing is pretty typical of non co2 tanks. The thing about heavily planted tanks is that they correct a lot of problems simply by means of mass. There is plenty of surface area for bacteria to colonize. There is lots of demand for nutrients. Light is filtered and scattered so it is not as intense. Just as V is suggesting.
> 
> 
> I tend to think the vast majority of problems in the early stages of a tank like this are bacterial in nature. I find they always have algae problems and really you just need to let it run its course and keep removing as much as you can until everything stabilizes a bit.


Bruce, the tank is about a month old.

I understand there may be diatom growing pains, BUT while I try and keep it at bay, I feel like it's going to choke out my plants before it "disappears" on it's own. Then the plants that are choked out by it will start dying and cause more problems. So for instance my Micranthemum 'Monte Carlo' is covered in it WITH some new green growth showing. Do I count out the original diatom covered parts and trim it out NOW or wait and hope the diatoms disappear and thus save the majority of the plants?

I attached a photo.

Thanks,
iso


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## anastasisariel (Oct 4, 2009)

Hoppy said:


> Algae and plants are not in competition for food. Algae require such minute amounts of food there is always plenty in the water for them, whether you have lots of fast growing plants or none. Algae are inhibited from starting to grow when there are lots of healthy, growing plants in the tank. The exact reason for this doesn't seem to be fully known. But, it is probably the chemicals released by dying or unhealthy plants that trigger algae spores to start to grow.


Best answer you will get. Most just say its plants taking in nutrients that the algea would have used but that really doesnt add up when we consider the conditions in which algea can thrive. There is something else going on we dont fully understand.

Im interested in whether a tank filled with healthy growing plants can prevent a diatom outbreak.


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## BruceF (Aug 5, 2011)

Keeping the tank as clean as you can will help. I usually clean the filters in new tanks every week and vacuum as much debris as possible, clean the glass, etc. I tend to let the plants fend for themselves. Some plants just won’t make it and if they are rotting I remove them. It is best in the beginning to start with easy plants but knowing which plants those are takes experience The stargrass should do well. It is a good fast grower. If it rots from the bottom let it float. Just get it growing. Take the anubias out once a week and clean it off. I use a soft toothbrush. I am not sure about the monte carlo. I have only recently been growing some. If you want to insure it survives take a bit out of the tank and grow it emersed in a small container for a while. Just let the moss grow. I sometimes take it out and rinse it in clean water

See if you can find some bacopa or some hygrophila, easy plants, and add some. Don’t run out and spend a fortune just buy like one plant a week and see if it grows. Starting a tank like this takes about 2 months to resolve itself and fill in and stabilize. After that you can start trying harder plants and doing a bit of re-scaping. 

I always run these tanks for at least two months before I start adding fish so go easy on the live stock. 

Something like that anyway!


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## dzega (Apr 22, 2013)

at tank startup i plant what ive intended in long run, then crank up co2 and add big mass of very fast growing floating plants. they dont have to be under floating category, any stem fast growing plant with big leaves will do.
when tank grows in i remove those floaters, gently lower co2 and introduce inhabitants.

im not saying its the right way.. its just how i do

edit, id drop a BN pleco in that tank for sure


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## isonychia (Nov 19, 2013)

I went out last night and picked up some frogbit and hornwort.

Right now it's soaking in Alum and after a 2 day soak i will put them in the tank.

I will also remove the anubias petite and clean them off. At the same time removing the anubias tied to rocks will probably release a lot of mulm trapped under the rocks so i will make sure to do a water change at the same time. Although, as discussed I assume excess mulm does not cause algae...LOL...who knows...

I am still doing multiple water changes and continuing my dosing schedule and compensating for the water change.

I asked another member, who has helped me A LOT, this questions. 
Wondering what everyone else thinks.

What happens to the diatoms when people say "mine just dissapeared" ?
Is that what really happens? Does the brown just disappear and will I be left with green plants again? This is the main reason I don't want to trim back the M Monte Carlo, as it does not look dead, just covered in diatoms. 

iso


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## Reff (Dec 1, 2016)

Hey ISO. I stumbled across this page from my own research. I'm having similar problems. I was wondering if you can provide any insight on how things played out? I'm also debating on cutting diatom coverred MC. What did you end up doing with yours? Did you have to remove the "bad" mc? Did diatoms eventually disappear or did you have to make changes to your tank to fend them off. Any advice would be greatly appreciated from you or others! 

Thanks!


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