I just bought a Fluval G6 filter and this thing is awesome. I was wondering if anyone uses a filter and a sump? I have never used a sump but Im about to get a much bigger tank than I had. I think I may need a sump for water dilution. I had a Fluval 305 and 404 on my 75g for two years. I had great success with both corals and fish. I kind of prefer the mechanical and chemical filtration. I dont have to add reactors to the tank. The G6 filter i have does so much more than the previous filters. It has temp, salinity and conductivity monitors as well as phosphate and nitrate removal. The waste that it traps goes into a collection cup so it wont degrade the water. I was wondering if I use two G6's, could I avoid a sump on a tank from 110 to 210. Thanks for the advice in advance! Here is a link to the info page of the G6. Fluval G6