I hope there are some experts here. I have a new external pump (Iwaki WMD20-RLXT) for my 60 gallon tank. The flow rate is 540 gallons/ hr at 4' head room. The flow is too fast and I want to restict it with a valve. If the pump can handle a maximum of 8' head room, is it safe to throttle back 30 - 50% of the flow?
