Let me give you a simpler option.

I have a 30 gal. trashcan sitting on my back porch. I make up my salt water there. The trashcan has a pump in it to stir it and aerate the water. I drain water into 5 gal. buckets so I can measure of much I am removing. Then I stick a 50 ft. length of tygon tubing onto the pump in the trash can, run the tubing to the tank and pump the water back into my sump.