thanks for all the help dudes haven't had this tank for long, the place I got it from insisted that one fx5 would be more than enough, since i set it up the water has been crystal clear with no ammonia or nitrates, but the flow has never looked enough to me plus my dovii, jags, and tilipias have dropped in activity which in truth was the main reason for the question in the first place, after all there used to 90 gallon running on three fluval 405's(wish i didn't sell them with my old tank now), im going to get two hyor koralia evo's tomorrow if the store sells them if not i will have to go for a different brand, but definitely getting 2 tomorrow no matter what,because i cant bear the though of one of my fish dying there all older then my kids lol, thanks again