Pump vs overflow gph rating issue.

[sde1500]

So I am in the process of getting a new tank up and running. Last tank was just a little 10 gallon nano that was nice, but too small. Now starting a 65 gallon tank with eshopps rs-100 sump.

I bought the tank used, so rather than risk drilling a back that I don't know if it is tempered or not, I got a hob overflow. Eshopps pf-800. Rated for 800 gph. For my return I have a Sicce Syncra silent 3.0. Rated for 714 gph, about 600 after my head loss.

The problem I'm facing now is, I turn the pump on and it quickly pushes water into the tank, the return section drops below minimum level and it starts sucking air. I first figured I was short a little water so I added a few gallons as it was running. The water level in the tank itself went up but the pump kept sucking air. The overflow looks like it's not draining fast enough. I didn't add any valve to the return because I figured the difference in gph should make that unnecessary, but is it as simple as I just need to slow down the return?

 

[GrampaDon]

Eshopps PF800 may rate it for 800 GPH max. But the proof is in front of you that it cannot run 600GPH.

Eshopps 800 use's a 1 in bulkhead. So I would cut the flow down to around 300 GPH. [A Sicce Syncra 2.0 would be a better match] Just closely watch the
U-tube for air bubbles collecting in it. If you see that happening ,increase the flow till they are pulled thru the U-tube. But try not to exceed 375GPH as that is where many feel is the limit for safely using a 1 inch that is also flowing air mixed with the water.

 

[ca1ore]

Gramps is right; overflow ratings are useless. A 1" based HoB = 300 gph, max.

 

[sde1500]

Well thats a bit of a bummer to hear. So time to rework my return to include a valve to cut the flow I guess. I'll stick with the 3.0, since its already in, and having the stronger pump gives me options if I want tee off the return to run something else as well.