One of the L134 Leopard Frog Pleco breeding tanks that we have. There is 2 large external filters running this tank but for added flow there is also 3 powerful internal filters all outlets to the left side of the tank sending flow across the surface down the right side and returning across the bottom this seams enough for the fish to spawn in the bottom right corner where the water starts to return back towards the filter outlets. There is the most turbulence in that corner. We fill the tank with 100% RO