Heres what im planning on doing....
For a 4-5gal a week (automated) water change.
You will need:
2x 250gph (roughly) pumps
3x timers
2x 5gal buckets, tanks, ect.
Some tubing or PVC piping
Total water change will take a total of 2-3 minutes
set one pump in your sump with a hose/pvc line going to a EMPTY 5g bucket.
set the second pump in a 5g FULL bucket premixed/preheated with salt water with a hose/pvc line going into the sump
hook a timer onto both pumps and use the third timer and connect it to your return pump
SETUP:
Timer 1: Return pump
Timer 2: Pump in sump
Timer 3: Pump in premix bucket
Time sets will just be an example. You can set up the timers to whatever time you want.
Timer 1 set 1:00PM OFF Timer 1 set 1:03PM ON
Timer 2 set 1:01PM ON Timer 2 set 1:02PM OFF
Timer 3 set 1:02PM ON Timer 3 set 1:03PM OFF
Water change complete within a few painless minutes.