I have a 125 stocked with 4 geo iporangensis,a rotkeil, an ebjd, 4 silver dollars, 2 plecos. I have 2 fluval 405s, and an ac110. The impeller covers on both 405s keep popping off, they are installed correctly and have been replaced since the problem arose. Fluval wants me to send them the filters since they are under warranty. I usually do a 50% wc once a week, if I do an additional 25%wc in the middle of the week should I be able to send in both 405s at the same time?