im planning on building a cinder block pond in my basement.i always plan ahead before i start anything.it will be about 5' x 10' and around 32" deep.that works out to between 500 and 600 gallons(wont know for sure till built,gonna round all corners and stuff)im not sure how to set up the proper filtration.should i buy a pond filter or would it be better to build my own filter? any help would be appreciated.im going to put african cichlids in it.