Pump & Overflow Sizing

[Tobman]

In determining what size pump(s) and what overflow rates are needed, besides head loss, one needs to figure how much of the total system volume needs to be cycled per day, say 5 system volumes per day. So for a 100 gallon tank and a 25 gallon sump, you'd need a flow of (5 x 125 gallons per 24 hours) 26 gph = 0.4 gpm.

Is that the right way to the estimate sytem flow rate?

What is the recommended number of times the system should be cycled per day?

 

[boz151]

It is traditionally looked at in terms of how many times you need to turn the tank over per hour, not per day. That number depends on what type of tank you are keeping (SPS Corals = 10x+ turnover per hour, LPS and FOWLR less turn is needed).

It also depends on things like closed loop setups, internal powerheads etc etc. The key with an SPS tank is good skimming and high water movement IMO, thus if this is your goal, you would want a high turn rate, plus some additonal water movement setup. If you are looking at a fish only tank, you won't need nearly the turn ratio as you will with a reef tank.

Just my 2 cents.

 

[sjm817]

Its more like GPH. Display size x 3 - 5 is what the flow should be after head loss. That is a general rule for non direct fed skimmer setups. Differences in sump sizes, etc can change that.