Acroholic;522598 wrote: Personally, I don't think it makes a lot of difference in the long run regarding flow rate thru the sump and skimmer function.
Assuming you have an adequately sized skimmer, the general function of the skimmer over time is that it is going to find a point of equilibrium with the organic levels it is pulling out. The skimmer is not always going to be playing catch up with the system, as most systems will probably reach a point where the level of organics produced by the tank is pretty consistent.
I assume it is like this: Organics = any uneaten fish/coral food + fish/coral products of metabolism (poo and and other secretions) + all other biological end products. If your maintenance habits are consistent, like regular water changes, cleaning filter socks (if you use them), amount of food you give, then the amount of organics made daily is going to be pretty stable.
Y<u>our skimmer is processing 1x,2x,3x the system volume every hour, 24 hours a day, 365 days a year. So how fast the water passes thru the sump it is in probably doesn't mean a lot in the long run, as the skimmer is only having to catch the daily organics made by the system.</u></em>
Before my tank upgrade, my reef system was about 300 net gallons. My Orca 200 was fed by a Mag 5 (500 gph), which for argument sake, passed 400 gph thru the skimmer, that totals 32 times the entire system volume a day, and 224 times a week.
Whether my sump is slow flow or higher flow doesn't seem like it would make a difference in the long run.
Regarding detritus, the sump flow rate would have an effect on how much you see in your sump. You'll have more stuff settle out in a low flow setup, as the water is not moving fast enough to keep the detritus in suspension to pass back to the return pump.