# diatoms and new tank



## Magdelaine (Apr 9, 2005)

I have a fairly new tank; about two months old, that just got stocked with fish after a fishless cycle and it's well planted with Aponotegons (I'm still waiting for my Java moss). I'm getting brownish algea gunk on my tank, rocks, and driftwood. I cleaned it up after my last weekly water change (25%) a few days ago and it's already coming back. I know it's a new tank problem, and I cannot test my nitrate levels, but that is part of it, right? My question is: will more frequent water changes help this situation? If so, how much and how often? When can I expect this problem to level out?

Luckily fish and plants seem pretty healthy so far...


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## MyraVan (Jan 19, 2005)

I have had brown algae in one of my tanks almost since it was set up about 6 months ago. I'm pretty sure it's the substrate at fault, as I have two other tanks with different substrates but otherwise pretty much the same... Er, I just realized that my two other tanks have more light than the one with the brown algae problem, and brown algae is associated with low light. So it's either my substrate or the low lighting (30W on a 20 gallon tank) which is responsible for the algae. 

The only time it went away is when I went on vacation for 9 days and the fish didn't get fed because I had assembled the automatic fish feeder incorrectly. (The fish were fine when I came back, just hungry!) When I started feeding again, the brown stuff returned.

So I don't have any real solutions for brown algae. We will move in a couple of months and I'll change the substrate then. If that doens't work I may look into getting a couple of otocinclus catfish, since they are supposed to love brown algae.


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## Damon (Jan 18, 2005)

Low light is one of the causes as well as poor water flow but it still comes down to the water hardness. You won't find diatoms (brown algae) in soft, acidic waters.


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## MyraVan (Jan 19, 2005)

Ah, well we have hard water too, which is also probably contributing to the problem. Still, my two other tanks have hard water, but no brown algae, so it's probably the substrate or low lighting that's making the difference in the tank that's plagued with it.


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## TheOldSalt (Jan 28, 2005)

Watr changes are generally no cure for diatoms, since the new water only brings in new minerals for the diatoms to use. The reason that this stuff is such a plague in new tanks is that new tanks are very rich in available minerals and low on competition for the them by plants. As the minerals get used up or coated with bioslime and made less available, and as the plants consume what remains, the diatoms fade. Soft water tanks, as Simpte said, don't tend to have this problem so much, for the obvious reason of not having as much in the way of silicate & minerals in them.
Lighting, of course, also makes a big difference, in that diatoms prefer low light while green plants prefer higher light levels. However, it's not uncommon at all to see brightly lit tanks still full of diatoms, and those tanks usually have plenty of diatom "food" in them like hard water or sandy substrate.

The good news is that it does eventually go away. Be carefull when cleaning it up to remove it from the tank without letting too much of it escape back into the water. By harvesting the diatoms, you are haresting their food. If they escape, they release their bound nutrients back into the water when they die, prolonging the growth of this pest.


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## Magdelaine (Apr 9, 2005)

Oh, joy! That's exactly what I've been doing, letting them fall back into the water...

It's good to know that water changes won't make a difference (and might even help them along). I do have nice hard mineral rich water, so I guess I will just try to plant the tank more heavily and be patient. It just makes the tank look so grimy...


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## Damon (Jan 18, 2005)

It will pass. No need to worry. And its harmless (in fact, if you have to have algae and we all do, brown algae is the one you want to deal with.) Nice pic in your avatar btw.


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## Guest (Jun 7, 2005)

*Hi ! Do you know, where i get a picture about blackish thoracatum catfish ??*


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## euRasian32 (May 19, 2005)

rabo said:


> Hi ! Do you know, where i get a picture about blackish thoracatum catfish ??


Hello welcome to fishforums. This is a bit off topic but here you go...

Is this the pic you're looking for?
Hoplosternum thoracatum ( now Megalechis thoracata)

Just a suggestion. You should formally introduce yourself in the "introductions" section, then you can fill your thread with questions. You'll be surprised in how many welcomes and helpful information you'll get.

C


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## Magdelaine (Apr 9, 2005)

*Update*

Hey there, I thought I would post that as of last week's water change where I added about 3/4 of a gallon RO water for a 30% water change on a 10 gallon tank, my diatom growth is much less (maybe half what it was the week before?). I think I will continue to add between half a gallon and a full gallon RO water with each water change from now on, as well as clean as much as possible once a week.

I'm hoping with the addition of more plants this will settle down completely.


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