The filter is for a 90 gallon tank which currently has an Emp 280, a Fluval 304, and a 350 magnum for filtration. The magnum is running ver poorly and I don't want to fix it so i am just going to buy a new filter. The Fluval 404's are on sale this month at the LFS for very cheap so I was thinking of buying one. What would be a better filtration combo: Fluval 304 + 2 Emp 280's OR Fluval 304 + Emp 280 + Fuval 404? I already have 1 Fluval 304 and 1 Emp 280, so please vote above and tell me which would the best third filter to buy. If you have any comments, please post them! Thanks