[ejwsr]

I need to cash a reality check here.

My understanding is that in an LS/LR system, the biological filtration occurs in the display tank where the greatest mass of the biofilter is. The purpose of a sump is to provide the mechanical filtration of suspended particulates through filter media and protein skimming, as well as chemical filtration if so desired.

Flow rate has the function of ensuring detritus doesn't settle on the substrate and corals, as well as duplicating the wave action for the reef zone you want to build.

Does it follow that given a 100 gallon tank with a desired total flow rate of 1500 gph that 750 gph sump flow and 750 gph tank flow would give you maximum filtration dwell time and target flow rate?

[NATIVEVAMAN]

If you have the appropiate amount of live roc. (1.5 pounds per gallon) and live sand 3 to 4 inchs's 4 is better) the only other filtration you will need is a skimmer with a boost from a refugium full of your favorite algea.Dwell time in the tank should not be an issue if you are turning over the water 15 times an hour. However most people consider 10 x turnover a minimum and 20 x is just ok 30 is better. Keeping particulates suspended is only one job for flow,the other is moving food to filter feeders like coral and clams.Some fish even prefer high flow rates and will be seen playing in the flow of power heads.But you get an "A" for research efforts.

[ejwsr]

Thanks for the information. I think that I have to update my plan a bit, but mainly pump sizing.

[NATIVEVAMAN]

On the front page of reef central there are several flow rate calculaters.There is one for pump by pump calulations including fitting and head height. And one for drain flow by pipe size.These will help a lot.