I had started a new 20 gallon a while back and added a few fish , lots of rock and new bulbs on a dual t5 setup. I have had green algae build up on glass and hair algae start forming also on rocks. I tested nitrate with about a 15 ppm and phosphate at about .25 ppm. This is the first time ever using a phosphate test and I'm curious if this should be at zero. I have not performed my water change yet for the week but will do so tomorrow and retest. Also I just added a nano skimmer on it which I desperately needed to bring nitrate down. I have some zoas and green star polyps only. Do you think my problem is my levels or what else do I test for. I have the lights about 6-7 inches above water level. Thanks for any advice.