Sell the pump, buy a proper canister. Just my two cents.
After really wanting to build a DIY canister and after reading many, many threads, I fully agree!
DIY canister filter seem to fit a couple different types. One is the type which never is completed to be a satisfactory filter. The second group is the ones who finish but have to admit they are not using the filter and wish they had not biult it. A great deal of time , effort and expense often results in a filter which does little but make the builder wish he had not started.