I had a 50-gallon many years past. A lot has changed since then; live coral for one, prices for another. Also, a large selection of fish. Back then there were really only 3 Clownfish to choose from. I have a 29-gallon saltwater tank (because that's all the room I have for one) with just a few live corals in it. I guess I have a diatom film all over my coral. Is that bad? Also, one of my coral has turned from green to yellow. I bought 5 coral and I'd say 4 lived. One died but I see numerous "sprouts" all around it. I'm cautious not to add fish until the coral looks more accumulated. Question do I run just blue light only to help the corals grow? Someone said to go dark for a few days, it won't hurt the coral but the diatoms might die off.