I have 4 poly tanks similar to water hauling tanks that equal about 1500 gallons total. I also have an IBC food tote that is 275 gallons that contains all of my media for biofiltration. This all flows into a parabolic sieve that screens off the solid waste before entering a high pressure bead filter to captures finer waste. I don't understand why the males are supposed to be seperated. My males are just reaching maturity about the time we stock them in May. This is evident as their pink tales and bellies start to show which is a sign of mature males. I do know they are quite agressive if kept together during breeding but you shouldn't have that problem unless you try to keep them in high densities for an extended period of time.