I don't even use a skimmer, my only filtration for FOWLR is the live rock itself, live sand, and HOB mechanic filter. Its been running almost 2 month(2 month in about 5 days) now with 2 ocellaris clown, and all the parameter reads 0 ammonia, 0 nitrate, 0 nitrite, 8.2 ph with a salinity of 1.025. Water is crystal clear also...doesn't necessary need to spend all that money to keep a FOWLR tank. Unless your going reef, then I can't answer that yet as I still got more homework to search 