[Bloodasp]

I'm gonna use the same car analogy. Going too slow means you are burning all the fuel that goes into the engine but you are not utilizing all the energy that the car is capable of, going too fast and you are not burning all the fuel that goes into the engine. In either case you need more fuel to get to where you want to go. The sweet number according to experts if I am not mistaken which they say would be fuel efficient would be between 60-80.
In a way if you have a tank that is 100 gal and you have a skimmer that has a pump rated at 800 gph and you have a turnover rate of 1 that would just mean that at least the same water goes through the skimmer 8 times. If you have a turnover rate of say 40 that would mean water would just be passing from your tank to your sump without even going to your skimmer. It you go around say 4-8 then the water would at least pass through your skimmer at least once or twice. I think that would be efficient enough. Going too slow and you are just going through water that has already been stripped of all those waste and oil and going too fast and you are not getting stripped at all.
Same thing with the heater if you have it in your sump. If it is too slow then the water is not heated up with evenly, if it is too fast then the water just passes through it without getting heated up at all.
best way is to just match the capability of your equipment with the turnover rate of your tank to your sump otherwise you are either wasting energy either it is just being redundant or not doing the job at all. It is going to be a trial end error thing but you will get the feel for it as it goes along.