Can Someone Finally Clear This Up For Me?

[VaegaVic]

Over the years I've heard so many things that apparently cause algae to grow:
- Nitrates
- Phosphates
- Ammonia
- Liquid Ferts
- Lack of CO2.

Which is it?
I personally always believed it was Ammonia and lack of C02 (obviously in ratio to the plants in the tank).

But now companies like Maidenhead aquatics sell things that remove phosphates from the water apparently stopping algal growth?

This has been driving me nuts for years, which is it?

 

[drobbyb]

There are many things which can cause algae to grow. The phosphate removing resins only work if phosphate is the culprit.

 

[MewMew42]

agreed^ which is why people have many problems with getting rid of it

I personally believe that the most common ones that cause algae are too much sunlight, nitrates and phosphates - nitrates and phosphates can come directly out of your tap sometimes in large quantities it only takes a miniscule amount of phosphates to cause algae growth

MH do phosphate tests now [or they should do, by the JBL testing kit?] to rule out if thats the problem, the removing products do actually work, good ol' jbl =]

 

[MOW4T]

sunlight i think. i have been very lucky and have never once seen algae in any of my tanks, as when i started someone told me not to have thetank in direct sunlight, following this rule as said has worked very well for me

 

[nmonks]

Your mistake is to assume all algae are the same thing. They're not. At least two KINGDOMS of life are involved, the bacteria (i.e., blue-green algae) and the protists (all the other algae). Even within these two groups there's massive diversity, from the silica-using diatoms through the the chlorophyte green algae strikingly like higher plants in their physiology. So trying to ascribe a single cause to algae problems is rather like trying to say cockroaches, foxes, and pigeons all want the same thing. Yes, all these are pests, but they're also using entirely different resources and operating in completely different ways.

However, you can make one generalisation, and that is algae tends to be a problem in tanks that aren't "balanced". Precisely what this means depends on who you talk to, but the basic idea is that tanks with more light and nutrients than their stocking of plants can handle tend to be the ones that get algae problems. So blue-green algae for example do tend to be more of a problem in overstocked, under-filtered tanks with direct sunlight, hair algae tends to be a problem in tanks with just slow-growing plants, and so on.

Put another way: tanks with bright lights, fast-growing plants, nutrient-poor water, and moderate stocking levels tend not to have algae problems.

Cheers, Neale

This has been driving me nuts for years, which is it?

 

[Assaye]

Different algae is caused or exacerbated by different things.

Typically light + ammonia = algae.

However, some species of algae grow when CO2 levels are too low or fluctuate too much.

Nutrients, such as phosphate and nitrate, don't cause algae but they certainly help it grow once it's there.

There is loads of good stickys in the planted tank section and on the UKAPS website.

 

[Dave Spencer]

The problem with alga in our tanks is that precious little work has been done in to assessing what are the root causes of algal blooms. Unfortunately, this results in the tired old argument of excess nitrates and phosphates being the root cause, due to the fact that the real study has been carried out in various lakes and waterways.

Every tank I have set up flies in the face of excess nutrients causing blooms, so these ideas cut very little ice with me, irrespective of what peer reviewed articles on Florida lakes people want to quote.

The only serious thought that has gone in to the causes of an algae outbreak in our tanks appears to me to have come from the planted side of the hobby. OP, if you want a bit more insight in to alga and their causes, I can PM some excellent sites which will answer your questions.

Dave.

 

[nmonks]

Dave,

I don't think anyone has argued that nitrate and phosphate are always the causes of algal blooms. Coming from a biology background, I'm probably as aware as anyone here about how eutrophication works (I've had to teach it to A-level students, for a start). And certainly, one symptom of eutrophication is an algal bloom. But "high levels" of nitrate are relative, not absolute, things. High and low levels of nitrate in the open sea would both seem trivially small compared to nitrate levels in, say, a garden pond. So while a miniscule nitrate increase in the open sea can (and does) cause a dinoflagellate bloom, you'd need a much bigger increase to produce a green algae bloom in a pond.

On the other hand, I agree with you that just because a tank has a relatively high level of nitrate doesn't mean it will automatically get stuck with an algal bloom. I've seen quite heavily stocked tanks with nary a trace of algae. My own tanks have little more than a wiping down of the front glass every few months, despite containing lots of fish.

But I will return to the key point that many experienced aquarists agree on: serious algae problems, in particular blue-green algae, are associated with tanks that have relatively poor water quality, too little water movement, and too much light, especially sunlight. Moreover, it is very easy to prevent algae problems simply by keeping a tank clean, doing regular water changes, stocking with fast-growing plants (floating plants are ideal), and providing sufficient light for those plants to do well. The addition of algae-eating snails and shrimps also helps, but in conjunction with the other things, rather than instead of them.

Cheers, Neale

 

[Dave Spencer]

Dave,
But I will return to the key point that many experienced aquarists agree on: serious algae problems, in particular blue-green algae, are associated with tanks that have relatively poor water quality, too little water movement, and too much light, especially sunlight. Moreover, it is very easy to prevent algae problems simply by keeping a tank clean, doing regular water changes, stocking with fast-growing plants (floating plants are ideal), and providing sufficient light for those plants to do well. The addition of algae-eating snails and shrimps also helps, but in conjunction with the other things, rather than instead of them.

Cheers, Neale

I agree very much with the above. These are all observations and conclusions that any aquarist can come to themselves, just by applying an open mind to what is going on in their tank.

Further to this, my experiences with BGA are that it always originates in a fine substrate such as sand, where the substrate receives sunlight. I quickly get rid of BGA by either blocking off light to the substrate with black tape (not my preferred option as it looks ugly, or directing a powerhead at it. A few people have attributed BGA to low nitrates, which could be an indirect result of a lack of water movement, but I personally am not in a position to agree or disagree with this.

There are two ways of knowing when my CO2 cylinders need changing. Either by keeping on top of the game and monitoring the pressure gauge regularly, or wondering for a couple of seconds why I am suddenly starting to see staghorn and BBA, before the penny drops and I remember that I have been less than meticulous in monitoring the cylinder pressure. I strongly believe that staghorn and BBA are CO2 related.

Ever since I have started new tanks up with Zeolite, I have never seen brown diatoms. It is a loose correlation, but I feel brown diatoms appear when there are sufficient ammonia levels ie an immature tank. All my tanks are started with mature media, mulm, Zeolite and daily 50% water changes to keep ammonia at bay, and diatoms never appear these days.

The triggers of algal blooms in our tanks is an observable factor I believe, and should not be confused with what actually feeds blooms, as so often seems to be the case in my opinion.

If I were to give a general answer on the causes of algal blooms, I would list too much light, not enough/fluctuating available carbon, insufficient nutrients (nitrates, phosphates, Mg, Fe etc.

All my thoughts are based on my planted tanks, and discussions with other aquarists running planted tanks.

Dave.

 

[nmonks]

I agree with this observation, but I'd elaborate somewhat, and observe that the roots of floating plants can become focal points for blue-green algae colonies. My suspicion is that it's the lack of water movement that is the key, given that blue-green algae favour swamps, mud, and other such still water habitats.

Cheers, Neale

Further to this, my experiences with BGA are that it always originates in a fine substrate such as sand, where the substrate receives sunlight. I quickly get rid of BGA by either blocking off light to the substrate with black tape (not my preferred option as it looks ugly, or directing a powerhead at it. A few people have attributed BGA to low nitrates, which could be an indirect result of a lack of water movement, but I personally am not in a position to agree or disagree with this.