Do you have algae eaters in the tank? Depending upon the size of the fish tank, you may want to have 1 or 2 algae eaters or certain types of catfish.
How long have you had the tank set up? I remember when you mentioned buying the tank, was it within the past 6 months? Sometimes when you first set the tank up (up to about 1/2 a year) the brown algae will grow until the environment stabilizes.
Have you been checking the chemical levels? If the phosphate and / or silicate levels are too high, it causes the tank / water to become a perfect breeding ground for brown algae.
Normally, petshops will test the water for you, for a minimum charge. You will need to bring a sample of water into the petshop and it only takes a few minutes. They can recommend what you need to correct the problem.
Also, overfeeding fish may cause brown algae to grow.
How often do you change your filter? Keep it clean.
Hope some of these hints help. I had fish tanks for years, it was a nice hobby, plus I worked at my cousins petshop for years, part time.
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Thanks. Right now there are 2 goldfish in the tank. Dirty little guys. I set the tank up maybe 2 months ago? The brown stuff is just starting to appear. I tested for nitrite/nitrate/ammonia/etc and it was all normal. I can't get a clear reading on the PH, may have to go buy a different test for that. Thanks for your tips. This happened with the last tank and I could never correct it, grr.
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