How to calculate gph of powerheads when oscillate in surge mode vs steady stream.

[Zizzer]

My question is, am I calculating the flow correctly?

I have 4 powerheads in total.

2, 1350's gph running at 100% and pulsing every 15 minutes pointed towards the top of water.

2, 1050's running at 50%, surging every 10 seconds. Pointed down at corals.

Since technically I'm only running 1, 1350 at any given moment and 1, 1050 @ 50% at any given moment, that would be

1350+(1050 x .5) = 1350+525 =1875gph
At any given time.

In a 75 gallon tank that would be 25 gph at any given time.

I would also like to add that my canister is supposed to be pushing 350 gph at all times adding another 4.67 gph to the 75 gallon aquarium bringing my gph to 29.67 gph.

When they say LPS needs 20 to 40 gph flow rate, is this how they mean to calculate it?
Or, am I over doing it?

 

[Mr. Mojo Rising]

its early, hard to understand all that math..... If we say the tank needs 20 times turnover as an example, then it is 75 gallons x 20 = 1500 gph total that you need. If you want 40 times turnover, then it is 75 gallons x 40 = 3000 gph total that you need.

 

[MarineandReef Jaron]

I think you are overthinking it a bit. I would go with the 2 1350s in a 75 for an LPS tank.

 

[Zizzer]

its early, hard to understand all that math..... If we say the tank needs 20 times turnover as an example, then it is 75 gallons x 20 = 1500 gph total that you need. If you want 40 times turnover, then it is 75 gallons x 40 = 3000 gph total that you need.

Sorry. I'll simplify a bit. 2 power heads running 1500 GPH at the same time would give me 3000 GPH. That would give a 75 gallon a 40 GPH turnover. Top end flow rate for LPS. But if the powerheads were oscillating in a pulse or surge mode, each powerhead would only be running half the time. Therfore the true turnover would be 20 GPH. Which is the lower end of the requirements for LPS.

So I guess my real question is, with two 1500 gph powerheads,

"am I really providing 3000 gph if the 2 powerheads are oscillating?"

"Or am I really only providing 1500 gph since they are oscillating?"

 

[arcangelreef]

You are way, way overthinking this man..

 

[YOYOYOReefer]

Ya. No such thing as a one sized solution. It matters on your tank size. Your rockwork and your corals. its about having the flow in the right places not just a number

my 80 gallon is 92x22x12 high. It’s got 2 biggest cross flows on each end and 3 Tunze the back wall. But it’s 8 feet of lps packed

if it was not packed with coral I could get away with half the pumps