Hi my phosphate levels are pretty high & I think this is due to the amount of tap water i used when I originally set my tank up. Since realising this mistake all my water changes have been done using RO. Other than doing a huge water change - which I can't because I don't have enough RO - is there anything I can use to lower my phosphate levels? If its not possible I suppose I'll just have to buy a large amount of RO & get on with it. Thanks