[Wet Thumb Forum]-What promotes algae growth?

[imported_aspen]

roger, i have been reading these forums etc for a couple of years, and the one thing i have decided about algae growth, is that no-one really knows why algae grows in one tank, and not another. in my own experience, i have tried all of the theories, and have discovered a few things about algae.

algae will take off in a new tank, if given half a chance and some fertiliser, regardless of which nutrients are added, or in which ratio. after some time, and a few algae bouts, the algae seems to just go away. that is, provided you give the proper light, co2 and nutrients to grow plants, gradually. this seems to take 2- 4 months, depending on light, co2 nutrient levels, and number of plants you start with.

one other thing i've noticed, is, that while algae will grow on the glass and the substrate, the leaves of the plants, usually in the area of most intense lighting will usually be much more algae free. logically, there should be more algae on the leaves of the plants in the higher light areas, than on the substrate, but there you go.

there are more questions than good answers about how to grow algae, or how not to.

i starve a tank to start with, start with hygro polysperma, etc and slowly ramp up the fishload and the growth of the plants. then swap in nicer plants as the tank matures. it works for me.

rick

[Roger Miller]

I thought that aspen's post to an earlier thread raised an interesting question, so I'm using it to branch a new topic.

[Roger Miller]

I thought that aspen's post to an earlier thread raised an interesting question, so I'm using it to branch a new topic.

[Roger Miller]

Rick is right. After years of questions and answers about how to *prevent* algae growth I think our best answer is simply that good plant growth appears to suppress algae. Maybe if we can get further if we take a different angle.

What factors promote algae growth over plant growth? The answer certainly must vary with the kind of algae in question.

In my tanks:

1) New tanks are prone to problems with a lot of different kinds of algae.

2) Short term declines in CO2 levels and moderate light levels promote diatoms

3) Low light promotes red algae growth over plant growth, and extra CO2 in the system produces a *lot* of red algae growth.

4) My tanks get a kind of soft, dark green hair algae that grows among plants in shaded areas with poor circulation.


Roger Miller

[Wheeler]

I find the opposite of what Aspen relates:

When I start a new tank, I begin, from day 1, with nutrients at 100%. I don't see any algaes untill the 2-4 month....Then slowly the little threads and green spot show up, then BBA after the 4th month or so.

BBA is the only algae that I seem to be able to grow with any sort of abundance. I blame my tap water.

I have, recently, scaled my fert dosing WAY back, and that seems to be to the benefit of plants, and dismay of algaes. I had always just assumed that a surplus of input (ferts, etc) and a deficit of output (plant growth, water changes, etc) were the primary cause for algaes. I think that I might be paraphrasing Arthur Westover there. Seems logical enough to me and congruent with my experience, though Van Grow will surely dispute this..... I don't know how he runs his tanks so rich with out problems.

Are the requirements of algaes that much different than higher plants?

Best wishes,
John Wheeler

[imported_Allen]

This is quite true... we had a similar long discussion in our local forum and ended up concluding that even the "experts" don't really know for sure how algae ticks...

We ended up giving a general rule of thumb

Healthy Plants = Less Algae... thats about all that could be said.

As for my own tank, I've had experience with 4 kinds of algae

1) green spot algae... which has plagued me since the start of my tank... Incidentally, has anyone noticed that spot algae grows much better in areas of poor circulation?
2) brown algae... none in my tank itself, but in my reactor and filter pipes. Speaking of which, a friend of mine tooks some snails, and put them in his reactor... he then sealed the reactor with a fine netting which prevented the snails from leaving... since then his reactor has been spotlessly clean.
3) BGA during the period when my daughter was born and my tank got badly neglected for several months
4) A green bushy algae which clings to my backing... So far its not an issue and I quite happy to mechanically remove whats there when I do a water change.

Allen
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[imported_aspen]

how to grow algae: add nutrients and light, and there you go, algae, seemingly right out of thin air. i believe the q is, 'what inhibits algae'. algae rarely grows on leaves that are thriving. it will almost always grow on my substrate.

people talk about the theory that plants will 'out-compete' algae. that is bunk. in a tank with consistent raised levels of nutrients, there is no out-competing going on here. there is food and light enough for all. we try and make our tanks a perfect place for plants to grow, yet algae seems to be inhibited. by WHAT?

there is a process going on in a tank, which allows 'the plants we like' (or something else possibly) to inhibit 'the plants etc we don't like'- the algaes and bga. when we discover what that is, we will be in the position to easily inhibit algae, while having thriving plants. no theory i've heard to date answers this question.

rick

[Roger Miller]

The question was "What promotes algae growth over plant growth" not simply "how to grow algae'. Light+nutrients grows both plants and algae, so by themselves they don't answer the question.

I have a unproven theory that algae growth is promoted by nutrient-deficient plants. This is the flip side of the idea that algae are suppressed by healthy plants.

Many algae are capable of heterotrophic growth, using simple sugars in solution in place of their own photosynthetic products. Claus Christensen considers it to be proven that blue green algae can use organics from the water. He wasn't so agreeable that green algae could do the same.

Plants leak metabolic products and (again according to Claus) raw nutrients into the water. There is published speculation that the leakage of metabolic products is an evolved-in mechanism. Aquatic plants leak metabolites to promote algae growth on their leaves. The idea is that herbivors graze on the algae growing on their leaves rather than on the leaves themselves.

I reason that plants that are nutrient-limited will leak even more metabolites. Nutrient-limited plants receive sufficient light and CO2 to fix carbon into simple organic molecules, but they are missing one or more of the nutrients they need to process the simple organics into more complex molecules. I expect the products to build up until they are lost into the water. I think it has been shown that nutrient-stressed algae will leak metabolites. The idea that plants will do so is my speculation.

We have whole classes of algae and blue green algae that thrive in aquaria under conditions of low light and low circulation. I think those algae may thrive in aquaria because the plants promote their growth. Stop the plants from promoting their growth and the algae will go away -- or at least fail to thrive.


Roger Miller

[imported_Allen]

Roger,

I read a previous posting of yours with great interest (now archived) about a conversation between Claus christenson to Cavan Allen... If I remember correctly, you were talking about DOC.

This got me thinking... would the introduction of enzymes which help break down water borne organics help in the battle against algae. I know nutrafin sell such a product.

To be honest though, my own understanding of DOC is severely limited... Its still uncharted waters for me.

Allen
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[Vicki]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> green spot algae... which has plagued me since the start of my tank... Incidentally, has anyone noticed that spot algae grows much better in areas of poor circulation?
<HR></BLOCKQUOTE>

No, I sure haven't. In my tanks it is exactly the opposite; green spot algae thrives only in areas where water circulation is high. In my 120 gallon, the barteris that are planted close to the filter outflow (and most particularly the leaves that are directly in its path) tend to become covered with green spot algae very quickly, even if they're new leaves. Leaves lower on the plant that are out of the flow (and also,it should be noted, much more shaded) don't accumulate near as much. I find the same to be true in my 55 gallon.

Green spot algae is pretty much my only issue, and it never grows on the glass--it's almost totally confined to anubias leaves. Once in a while I'll notice some on an E. tennellus leaf, but it's almost always a leaf that's dying anyway.

I too have gone through the assorted algae plagues in new tanks, but when I set up my 120 last June, I went full bore with lights, CO2 and fertilizers right away and filled the tank with fastgrowing plants. I had a watersprite thicket you wouldn't believe, and I never saw any visible algae of any kind except for a smattering of brown and green dust algae on the glass--no more than you'd expect to grow between water changes and glass cleanings. I'm sure the six young SAEs that were the first fish in the tank had a lot to do with that also. After about four months, I began replacing the fastgrowers, and removed the watersprite altogether; except for the green spot algae I mentioned above, I've had no problems. I was hoping that would begin to disappear as I began dosing phosphates, but so far it hasn't; the levels are never higher than .5, and closer to .2 most of the time, maybe I'm just not dosing enough. Anyone have any suggestions?

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