Return pump size for 20 gallon long?

[MoshJosh]

What size pump to return from 10 gallon sump to 20 gallon long?

 

[nuxx]

Would just look at companies that make a range of DC controlled pumps and go with their smallest model.

Being controllable you should be able to be fine with their smaller pumps.

 

[TopShelfAquatics]

When it comes to return pumps the "standard" seems to be 10x turnover so something around 300gph would work, but with that being said you can always get away with a little less or a little more. Depending on your plumbing at the bare minimum something like a Sicce Syncra 1.5 would work. From there you can go to a larger size if you are going to be running any equipment off that pump. DC pumps are always nice because you can always turn up or turn down the power.