I should of stated I read about the o-ring swap, thanks for the advice. I was worried about the hw-603 sunsun prefilter being able to handle the flow, that's why I was thinking of getting a smaller odyssea filter like a 700, removing the pump, using that for the prefilter and using the 14i semi filled with crushed lava rock. I'm a click away from ordering the 14i now lol.