Thin,
I have t-5 lighting, one blue one white, on at 11a off at 7p. They are mostly gone first thing in the morning then bloom with the lights. There is very little direct sunlight on the tank. I thought they were dinoflagyllates so I was agressively vaacuming the substrate, I also got so sick of them I took everything out of the tank, replaced the sand bed and started over...no change...wow I got frustrated. I have one sailfin tang, 2 clowns and 1 small yellow tail damsel. I have a large shrimp, large brittle star, snails (which seem to be dying off) and hermit crabs. My zoa's and corals are doing great but the frog spawn is tinged brown..which is why we thought dino's. I did a fresh water bath on that, which lightened it up a bit. I am adding more sponges, corals and have 2 fish in QT (coral beauty and a flame angel) waiting to go into the tank. 2 more weeks. Then I will be adding a scooter blemy and one more fish...possibly yellow or blue tang. Then I will remove the two clowns and put them in my smaller QT tank which is regular salt not hypo. I had a major oops with my main tank and got ich with my blue hippo and ended up loosing my hippo, coral beauty, fox face and swallow tail angel...won't do that again. Actually Bully the brittle star is the only original tank mate we have...he is called Bully because he was eating other tank mates. Is there any other way to get rid of the diatoms? I have had them for sooooo long. (but I have been doing agressive vaac's since before that)