john&jen

In my 75 there are brown spots growing on the plants and driftwood. I am assuming they are diatoms, from what I've read in other posts. I'm just looking for a better explanation and remedy. Time and waterchanges? This is the same tank I just posted a question about "worms in tank". I plan on a few changes to decrease the salinity.

susitna-flower

How long has your tank been set up? Usually it takes a month or more for this to disappear. In a word, yes. Time and waterchanges / gravel vacuuming.

I believe otoes like to eat the stuff...If you don't already have algae eaters, they would be a good choice, even if you don't have lots of algae. 5 or more would be a good choice.

What fish do you have in the tank now. Is it cycled? Do you test the water?

john&jen

The tank has been up for about 6 weeks. It is tested and cleaned regularly. Livebearers, 2 snails, tetras, upsidedown cat, rainbow shark, and pictus cat. It is fully cycled...finally! We used biospira and it did not work well at all in this tank.

sirdarksol

One question in addition to what susitna has said/asked.
How much light does the tank get? I'm counting indirect light here, too. I've got a spot in my living room that doesn't get much direct light, but light bounces off the light-colored walls and the shiny hardwood floor, and any tank in that spot ends up with a diatom problem unless it's just loaded with plants (which absorb the nutrients the diatoms need).

I also have a theory that Phosban or RO would do the trick, too. In addition to getting rid of phosphates (which the diatoms need), it pulls silicates out of the water. Since diatoms make their "shells" out of silica, I think that either method would deprive the diatoms of everything they needed to live. (This has not been tested at all, it is merely conjecture based on the knowledge of how diatoms live)

Johawk

I have a similar problem in my tank. Based on what sirdarksol says about the phosphates, would not feeding fish flake food for a while help the problem? I know from what I have read on this site that most flake food will lead to higher phosphate in the tank.

sirdarksol

Even just avoiding overfeeding would help, though switching to a more concentrated, nutritious diet could help, as well. I think the issue is that flakes are usually made with fish meal, which is about as good for a tank as ultra-refined flour is for people. It's easily broken down into component molecules, and I think phosphorous might be one of those (not sure, though). At the very least, it will add nitrogen, which also feeds the diatoms.

I feed my fish Omega One fish food. Much of it comes in flakes, but it seems to have been made with whole fish (though I worry about how well controlled the labels of fish food are).

john&jen

I just did a 50% water change...and it was nasty! I also did not replace the salt, so the salinity should be half of what is was. I will watch closely.

sirdarksol

I just noticed that you said you have salt. I missed that before. I know that most cats dislike salt. It puts way too much stress on their bodies. Tetras probably dislike it, too, as they are usually softer water fish. The fish in that tank, other than the livebearers, probably dislike the salt, so it's good to be phasing that out.

john&jen

The pictus is now coming out during the day. Watching everyone else for changes.