live sand turning brown

[marco]

I started a 20 gallon tank about 3 months ago. It has 20 lbs of live rock and a 2 inch sand bed. My filtration is a emporer 280 and a berlin skimmer. It's stocked with a strawberry chromis a serpant star a sand sifter star and three snails. About a month ago I noticed a brown, some what slimy spot forming on top of the sand, so I removed it with net. Now it wont stop. If I keep it up I'll have no more sand in my tank. What should I be testing for? ph,ammonia,nitrites and nitrates are fine.

 

[nacl-h2o]

sounds like cynobacteria

 

[demosthenes]

It is possible that it might be cyanobacteria, but I won't be sure unless I can see pictures, or the results of a phosphate test. Make sure you get a test that tests inorganic and organic phosphate. It may just test organic phosphate, and the reading will be zero. Then you are fooled into believing the reading to be 0, but it won't be. Once the organic phosphate is used up, the inorganic phosphate will convert into organic phosphate, and the algae will still be thriving in your aquarium. There are numerous ways to rid your tank of phosphate, including a number of chemical ways, but the two that I have found work best are making sure that you are not introducing phosphate into the tank through top-off water and water changes. Make sure your water doesn't have phosphate. The best way to make sure of this is to use RO/DI water. You can also use phosphate pads in your sump. As long as water is forced through the pad, they will work fine. I use them, because I can't afford an RO/DI unit. HTH

 

[jagnmeg99]

Marco---I had the same problem and posted the same topic, please do a search and look at the answers I got, that may help