I have had an algae problem for months now and I cant seem to fix it. I test my water with api test kits (i will be upgrading soon) and my nitrates are very low but my phosphates are at about 1. My rodi water tests 1 also for phosphates and im not sure why. I believe its the phosphates causing it but im not sure. Last night I installed a gfo/carbon reactor and my api test kit still says 1 for phosphates. Any help would be greatly appreciated, thanks.