No controller needed – target the flow you want and just buy the right pump. The one I spec'd gives you the flow you mentioned.
IMO, skip the whole idea of a controller or changing the return flow.
Instead design the
right flow into your pump choice before you buy.
It's pretty easy in most cases.
For my recommendation earlier, I assumed:
- 2x-4x the display size for your actual return flow rate. In other words, between 220 GPH and 440 GPH of actual flow.
- the main flow in the display tank is from powerheads
- the tank is 5' high
- that you have a sump under your tank with the return pump in or next to it
- that the return is a more or less straight shot up to the tank
If that's a good description of your tank, then the pumps I suggested (or similar) would all be good. No valves or controllers needed.
If you have any doubt, post up the details of your plumbing and we can see if the estimates and your requirements "stack up".
Will need to know:
- a pretty close estimate of the amount of vertical space between the sump and the return
- the total length of plumbing the flow will go through
- the number and type of fittings the flow will go through
- corrections to any other assumptions I mentioned
Hope this helps!