Enough flow in sump and DT

[Mombo]

Ive got a 120g tank cycling right now. I have a Jebao DCP-6500 that does about 1700gph in the sump and I have 2 Jebao SW8's in the DT that do about 1300gph.

My sump has about 30 gallons total water and my DT I would say about 100g total water. So 130g total.

Right now my return pump is just on full blast as I didnt have the powerheads until today. Now I am trying to figure out what I should set the return at.

I know with the powerheads doing about 25x DT turnover that should be decent enough. So I dont think I need to be blasting another prob 15-1600gph(considering plumbing etc) through the tank and sump. I am currently thinking about turning the pump down to about 60% which would put me at 900-1000gph through the sump.

Is that too much or enough?

 

[Heliarc19]

With your head pressure and pipe static and elbows,reducers you may not be pushing nearly as much as you think with that return pump. I say if your overflows are working well and skimmer is working well once broken in I would leave it. Are you running a manifold or do you plan too?

 

[mfinn]

With a 120 gallon display tank you really don't need more than 650-700gph going through the sump.
You will get more than enough with your return pump, but I would look at different powerheads.
I have a pair of rw-8's in my 90 gallon tank I'm just using as a fish quarantine tank. Even at full blast, they don't create alot of flow in it.

 

[Mombo]

Wont be able to upgrade the power heads for a while. I feel like they push a decent amount of water. I guess maybe the return being at 900 would give it a bit extra flow if they are not doing enough without it being to ridiculous in the sump.

 

[Mombo]

Does anyone know how much water is in a 120g 48x24x24 per inch of water? Trying to figure out how much water will siphon out of the tank if the return nozzle is 1 or 2 inchs below the water.

 

[Heliarc19]

Does anyone know how much water is in a 120g 48x24x24 per inch of water? Trying to figure out how much water will siphon out of the tank if the return nozzle is 1 or 2 inchs below the water.

5 gallons per inch

 

[Forsaken77]

Does anyone know how much water is in a 120g 48x24x24 per inch of water? Trying to figure out how much water will siphon out of the tank if the return nozzle is 1 or 2 inchs below the water.

Go to reefcentral.com and go to the homepage. Scroll down and on the lower left side you'll see calculators. The "sump" calculator will tell you how much water will siphon out and what size sump you should have. They already have a default setting for 2" of water siphoning out.

 

[Mombo]

I kinda just went for it and turned the pump off to see how much it would siphon and how much of the sump would fill up. It held it all!

 

[mfinn]

I kinda just went for it and turned the pump off to see how much it would siphon and how much of the sump would fill up. It held it all!

Done exactly that many times.
You can do all the calculations in the world and while they should be close, just a old fashion test run is what you need to do.
I usually do it several times, pushing it higher each time so I can use the most volume in the sump as I can, with out causing a flood, and give me a 1" or 2 breathing room.

Next time to figure out the calculation on paper, measure the inside of the tank and multiple, width" x front to back" x 1" = X". Then divide that number by 231. That will give you gallons per inch.