Flow rate

[bpitts4]

Is there a formula or calculator to determine the correct flow rate for your tank or even a sump/fuge? I am in the process of setting up a 180 gallon rr tank with a sump/fuge and want to put the correct return pump on the tank to acheive a optimal flow rate in the tank.

Thanks!

 

[eagle9252]

some say 10x turn over but do you want 10x going thur your sump and or fuge? i'm probably doing about 500 to 700 thru my sump and more in the tank with power heads

 

[ichthyoid]

bpitts4;826197 wrote: Is there a formula or calculator to determine the correct flow rate for your tank or even a sump/fuge? I am in the process of setting up a 180 gallon rr tank with a sump/fuge and want to put the correct return pump on the tank to acheive a optimal flow rate in the tank.

Thanks!

I just calculated that a 5x flow rate based on tank volume will assure that at least 96.88% of the tanks volume is cycled through the refugium each hour (assuming a 50% dilution ratio).

The flow rate within the tank should be much higher. Around 20x is often recommended and some SPS tanks can be higher than that (25-30x).

Examples:

Return pump size:
For a 180 gallon aquarium you would target around 900 gph through a refugium (180 x 5 = 900). This is often provided by the return pump.

Return pump + power heads:
You might target 3,600 gph flow within the tank itself, by using power heads (180 x 20 = 3,600). This number usually includes the total flow of both a return pump plus power heads within the tank itself.

 

[heathlindner25]

I have 80 times flow in my sps tank. is that really high?

 

[bpitts4]

Ok....so the plan is to put in 2 MP40's into the tank. Between that and the return pump there should be enough flow in the tank itself. The return pump of choice is going to be the Reeflo Snapper/Dart Hybrid which has a range of 2600 to 4300 gph. I am thinking that this should be enough for the flow inside the tank and should work well for the sump. I imagine with the head pressure and the length of travel that by the time it reaches the sump the flow will have decreased enough to provide accurate flow in that area. Thoughts?

 

[ichthyoid]

On a 180 you may want to consider a 3rd MP40 (if you have the budget), placed in the middle of the back wall.

You can run a very effective 'nutrient export mode' cycle this way, and it really keeps the tank stirred up and food, etc., suspended.

 

[ichthyoid]

heathlindner25;826241 wrote: I have 80 times flow in my sps tank. is that really high?

There is nowhere in nature, that I am aware of, short of a hurricane where those conditions exist naturally and corals grow.

Perhaps on a fringing reef, but that would be difficult to even measure accurately.

But hey, if that works for you great!

 

[bpitts4]

ichthyoid;826292 wrote: On a 180 you may want to consider a 3rd MP40 (if you have the budget), placed in the middle of the back wall.

You can run a very effective 'nutrient export mode' cycle this way, and it really keeps the tank stirred up and food, etc., suspended.

I was actually consiering adding 2 MP10's on the back wall evenly spaced out in the tank. This should be adequate.

 

[enderg60]

To keep things simple you want at least 3x turnover going through your filtration system.

Additional flow is REQUIRED for corals, how much depends on what you want to keep.

My 300 has about 800 GPH from the return(on a OM with 4 outlets and eductors on each so about 2400gph there)

I also have a dart with 7 eductors on it so thats over 10,000gph there, as well as a wave box.

There are definitely spots that could use more flow but I just put low flow corals there. I could easily double the flow in that tank and not even think twice about it, but what I have works for me.

Where and how many power heads or closed loop outlets you "need" depends on what corals you want and how your rockwork is setup, there is no easy calculator to do it.

 

[ichthyoid]

bpitts4;826297 wrote: I was actually consiering adding 2 MP10's on the back wall evenly spaced out in the tank. This should be adequate.

FWIW-

MP10's are not recommended for use on 1/2 inch glass, which your 180 will have. Some have used them anyway.

In any event, I wouldn't want to depend on the flow from them alone in a 180 gallon tank.

You could add some Koralias to stay in budget, but not my first choice.

Tunze also makes an excellent power head.