I agree somewhat with the guys above about not adding anything for a while, but if you must add something, zoos wouldn't be a bad start. They are usually pretty tuff. Start with the smallest cheapest piece you can find and give it at least a couple of weeks to see how they are doing before you put anything else in. Also, IMO, Phosbuster and Purpleup are not very good additives. First of all, how could adding something to your tank remove something? That just doesn't make sense. It may precipitate phosphate, but so does pickling lime and it is a lot cheaper. Secondly, Purpleup cannot increase both calcium and alkalinity which means that if it is doing anything at all, it is likely throwing off your calcium/alkalinity balance. Calcium and alkalinity should almost always be adjusted using a balanced method such as a two part additive like C-Balance, B-Ionic, or using other balanced methods like pickling lime or a calcium reactor.