Pump size for sump

[Tmanwa253]

So I have a 75 gal tank with a Eshopps 1000 overflow and a 20 gal sump that sits 3 ft under the tank what return pump (gph) is recommend and brands I'm thinking about Jaboa 5000 is this overkill??

 

[mcgyvr]

You want something that will push about 3-5x display tank size in GPH after head loss..
So if your pump is 4ft below the top of the display tank find the pump charts and ensure its capable of about 225 to 375GPH at 4ft of head
Some go all the way up to about 10x tank size in case they want to run reactors or other things off the return pump at a later date..

 

[Tmanwa253]

Is it bad to go past the 10x mark. I seen people say pump size should be at the max flow of the overflow box in my case the flow rate of the box is supposedly be around 1000 so I guess my question is there to much flow?? Is that bad for the coral??

 

[mcgyvr]

Is it bad to go past the 10x mark. I seen people say pump size should be at the max flow of the overflow box in my case the flow rate of the box is supposedly be around 1000 so I guess my question is there to much flow?? Is that bad for the coral??

A high volume/rate of flow through a sump would be seen as "inefficient" as you are just using energy pumping water up and down and not treating it at the same rate..

It is generally accepted that 3-5x is more than sufficient for the flowrate through a sump.. Your skimmer or anything else in the sump likely cannot process water at that rate (or anywhere near it) anyways.

A statement that one should always do the "max flow of the overflow box" isn't one I would ever say.. In general running anything in life "at the max" is just asking for trouble as there is no overhead for "surges" or other things that may cause you to exceed that rating.. Its basically a "safety rating" and you should NEVER exceed that and going anywhere close to it as a norm/typical isn't a good idea..
Now overflow boxes may have a "suggested or recommended" flow rate based on their size/design so there is something there that one would factor in.. You should really pick an overflow box rated in excess of your sump flow rate.. Not the other way around..

Typically people say 3-5x for the rate through the sump and then the rest of the suggested flow rates in the display tank are accomplished via powerheads.. Typically 20-30x is total flow rate recommendation for a low flow/starting out.. 30-50x is medium flow and 50-100x is high flow for SPS only tanks,etc...

 

[Tmanwa253]

So in my case being 75 gal with a 20 gal sump it should be ok with 1000 gph throttled down(being I may add realtor and other stuff later)should be okay then put power heads that would push around another 1500 gph correct

 

[Tmanwa253]

1000 gph on sump factoring in head loss and flow loss to fittings

 

[mcgyvr]

Return Pump
IF display tank is 75 gallons
THEN
Return pump = 3x75 to 5x75GPH after head loss so 225 to 375GPH after head loss..
(Must consult specific pumps flow chart to determine acceptability of pump given size above)

A reactor can easily be a few hundred GPH loss or more.. (all depends on type/quantity of reactors,etc...)

A valve on the output of a pump can easily be used to throttle the pump down to adjust its output.

Powerheads
With powerheads 2 pumps is better than one.. 3 is better than 2 typically as you can spread the flow out better in a tank
IF display tank is 75 gallons
THEN
Powerheads =
30 x 75GPH = 2,250GPH for a "general/lower flow system"
50 x 75GPH = 3,750GPH for a "medium flow/mixed reef system"
75 x 75GPH = 5,000+GPH for a "high flow SPS coral only system"

Your suggestion of 1500gph for powerheads is on the bottom end but would be ok for starters..