I run 3 sumps on 3 freshwater systems, cool water, mid tropical and tropical, each line of tanks is between 300 and 400 gallons.
I wouldn't go any other way.
Also do freshwater refugiums with aquatic and marginal plants, that contain freshwater shrimp.
And use fractionation on the tanks, and a freshwater pond.
Anything used for salt water, is workable for fresh.
click on pic.