Hello and Welcome to Aquarium Advice!
Depending on the amount of money you have, the fx5 is very costy, and the flow might be just too powerful. I personally own an Rena xp4 and two fluval 406, and they are just fine for a 300 gallon. I also run a 75 gallon sump but that's something else. The 406 will be enough, costing usually 290$ at retail price, compared to 519$~ on the fx5. You could also look into getting a Sump(usually a bit cheaper) or as i said, invest in a less ''advanced'' if I may say canister or Sun Sun canister filter witch are very popular due to their low price and high effiency.
and ClownKnife Fish