Continuous Siphon Overflows

If I invest in a CPR CS overflow what size should I get. I currently have a submersible rio 2100 pump pushing 692 GPH but will eventually upgrade to the Rio 2500 (792 GPH). Should I go with the 800gph version or the 1200gph version of the overflow??

 

I would go with a CS-102 to leave room for growth and error. You can always go below the rated flows, but not more.

 

I would say 800, if you get a disproportionately large overflow or pump compared to the other piece of equipment, you can get a pretty bad gurgling sound. Even with the Rio 2500, you won't get 792 gph. I think the 800 is a good match.

 

With a CS-102, you can block off one of the bulkheads. It essentially becomes a CS-100, since they both use 1" bulkheads and have the exact same box dimensions.

 

I would recommend getting a Eshopps overflow, and not a CPR. Much better designed and thought out units. You won't have to use an aquilifter with them either.
Also, you want the return pump to have a slightly higher flow rate, at head height, than the overflow. Dial them to match with a gate valve.

 

I would go with the 1200gph because you can never get more out of the 600gph if it's not enough later on.

 

i have an eshopps 300gph and it works great, you dont have to worry about power loss, they never lose syphon

 

For my 75g, I use the CPR-100, combined with a Mag 9.5 and a 30g sump. In the return line I have a UV filter and check valve (generally reduces the bubbles on a restart), and a ball valve to throttle with....though the ball valve stays fully open....until the filters get dirty and I take the lazy way and throttle return flow to stop the pump from sucking air...helpful when your walking out the door to work in the morning and see bubbles in the DT...