I am taking advantage of petco's $1 a gallon tank deal to pick up a 20 long. Most likely I won't set this up for a long time but I eventually will house some cacatuoides in it along with serpae tetra and probably cores. Would a circulation pump be needed to create the necessary water flow on such a long tank? I have two hob filters, a top fin power ten and a fluvial c2 but I'm not sure if they would do the job. Also would a circulation pump like an aqueon 500 be too strong for apistogramma?