is a fluval 404 too much for a 55 hex with about 6 datnoids and few plecos and a couple of small cats. tank is a grow out tank. should i also keep the the undergravel filter with a 802 on it? should i reverse the powerhead? should i turn down the fluval? is it better to run more bio media than carbon i have two trays full of bio media and two trays full of carbon? thanks