Just don't forget to take into consideration you head height loss ( distance from pump to were the water exits into the tank) And also there was a article I read that said what size of pipe is capable of carrying "x" amount of GPH,nd rather then have 4 returns ya could always just do one spray bar across length of the tank for good circulation, and surface aggitation I have one and it filly adjustable to point to the surface or right to the bottom ya can basically turn it to whatever dIrection is needed to optain what ya want or need