Rob,
My display is a 65 Gallon rimless, I've got a 30g acrylic sump, SWC Cone skimmer, and the entire system (as of yesterday actually) is running on an Eheim 1262 return pump.
Return pump tee's off to go to the main, then through my closet wall and up to a manifold which runs 2 BRS Carbon/GFO reactors, then it travels up about 5.5 feet to a 20 gallon fuge which overflows back into the 30g sump under the tank.
That is the main system --
Water changes are handled by the Genesis Renew, that pumps out water from the 30g sump under the tank, as well as the 25gallon container you can see in my pics. 1 gallon from each get metered in the Genesis resevoirs, then the new saltwater is dropped to the sump, and old water down a drain line that runs around my closet to the laundry room drain since the closet and laundry room (perfectly i may add) share a wall.
Top-off is handled by the Geneses Storm which is fed by the RO/DI and that is controlled by the Genesis RocV add-on to the Storm. What that does is measure the water level in the 25 gallon freshwater bin, once it's low it kicks on the RO/DI automatically, so there is always freshwater for top-off and for mixing salt.
As of right now I have my Renew system set on 2 gallons/day -- so about every 2 weeks I just turn a few ball valves between the two reservoirs, fill up the salt bin with 25 gallons of RODI water, add in salt, and I'm good to go for another two weeks.
It is not the cheapest system to setup, and I think anything smaller than a 65 gallon it would really not be worth the cost/effort, but I setup these bits before getting the light upgrade I really want, and it was well worth the wait for the light(s) to have the automation, and stability.