I'm planning to plumb my 240 gallon aquarium , from what I see I like the herbie overflow the best , with two standpipes , the question is , if I use a 1 inch overflow for main and a 1.5 for emergency , and I'll this work? I can't really find the flow rate of these online because different sites gives different answers , am planning to get 4-5 times turnover , thanks , ps. Will the 1.5 overflow be able to pick up all the water if the 1 inch clogs ? Thanks