We have an urgent situation now. I am new to salt water aquariums and an algae problem has gotten way out of hand fairly quickly. An now I have lost a shrimp and a yellow tang in less than 30 hours. I have tested the water with the following results: Ammonia = 0 Nitrites <0.3 KH = 6 PH = 7.5/6 I think there is a chance that it is possible that the algae is taking O2 out of the water and that is suffocating the fish. Don't know. What I have done so far is: 1. clean the skimmer (was clean last week but now was clogged with algae) 2. clean the BRS (carbon and GFO) 3. put a temporary air pump and bubble stone in to add O2. 4. a 20% water change I think my problem is that we have been topping off with RO water (but it is not DI). And we may have been overfeeding a bit (half a cube of frozen shrimp every 3 days and some tropical flakes daily). Lights are on 8 hours per day on a timer. The tank was up and running for a year and a half and we moved it (took everything out and cleaned the tank and put it all back including almost every drop of water) about a month and a half ago. My questions: 1. What can I do to save the rest of my fish? Urgent steps I need to take but haven't? I have an empty tank, start a temporary for the fish?? 2. How do I keep this from happening again? How do I kill off all this algae? What type is this? Thank you all for your help!