<a href=showthread.php?s=&postid=9407472#post9407472 target=_blank>Originally posted</a> by itz frank
I believe everyone hit it on the head with the Phosphates issue. I don't think it's your sand, nor the skimmer issue as i had a 20 gal for 9 months without any issues. However, if the algae on the sand is thick and a red it's a good chance is Cyanobacteria. Which is said to be part of the normal tank maturing phase. I think the best thing you can do is step your water changes up from a 2 gal every week to a 10-15 once a month. It's almost the same amount of water but the thing is that when you do 2 gal water changes you're only changing maybe 7% of your water. Which while may help replenish nutrients for the coral it's not doing anything to change the water composition(nitrite, phosphate, etc.). Where a 15gal. water change would be a 50% change and can drastically change the water composition. I don't think this is really an issue of anything changing, i think that you've just allowed phosphates to accumulate over time with the 2 gal water changes and with one good waterchange you'll see improvements quickly.
