I don't have a phosphate test, but id imagine that I have a high amount. What I meant by attacking the source is doing frequent water changes, twice a week, with RO/DI water to try to lower phosphates. I was also running skimmerless for a while too. I have a 30 gallon tank so a tang would be out of the question. What I think caused the HA in the first place was that I made a newbie mistake, Iwent away for 2 days and forgot to close the blinds.