I found that a 2217 with just blue sponges and some floss, with only an inline heater after the canister, wasn't enough filtration for my 50g. I had the same prefilter as you and found that it clogged up way too quickly and caused even lower flow. I dumped it for a SS mesh strainer, added a 2213 with CO2 reactor inline, and a Koralia 240. This setup provides enough filtration and flow for a moderately planted 50g. You may want to go with a 2215 or second 2217 to get enough water moving through yours.