what is my water flow rate...?

[flipteg]

i have a MaxiJet 1200 (~298 GPH) in a 30 gallon cube... with this, my flow rate is at about 10 times turnover per hour... i do not have a sump but i have a hang on skimmer with a pump rated at 500 GPH... when calculating the pumps' flow rate (in terms of keeping corals and inhabitants happy, and to keep detritus from settling in a dead spot) i wasn't sure if return pumps from sumps, filters, skimmers and such count...

[smiller]

Only tank water movement.

[jeffbrig]

Count whatever water is actually moving in the tank, regardless of whether it's a return pump, powerhead, canister filter, etc. Your tank's inhabitants don't know the difference. For example, a recirculating pump on a skimmer wouldn't count, because it just blows water inside the skimmer body. However, if you had another pump feeding the skimmer, the return flow would count.

Here's how I calculate mine.... In my tank, I have ~2500gph coming from the return pump, according to the pump calculator. A pair of Tunze Stream 6100s push 3000+gph each, but they throttle between 40-100% on a multi controller. A safe estimate would be 5000gph average for the pair. That's 7500gph in a 250g tank, so ~30x turnover. (You could argue it's actually higher because the actual water volume in the tank is a bit less than 250g, but calculating turnover is just a general rule of thumb, so it doesn't really matter.)

Keep in mind that in your case, if the skimmer pump is mixing air/water, so the effective water flow is actually MUCH less than the rating on the pump.