I've been trying to get rid of the cyanobacteria in my tank for about a month now with no improvment. I did get rid of my hair algae and dinoflagellates in a short time by shortening my photoperiod from 14 hours to 10 hours. It doesn't seem to be doing anything to the cyano, however. I siphon it of rocks and out of the sand and it begins to return by the next morning. I was looking at the different additives you can get to combat them but I feel like they would be bad for my tank so I don't really want to try them.\nWhat is an acceptable level of phosphate? I'm getting ready to test everything now so I will get the results up soon. Thanks in advance.