I built a stand out of 2X4's in the corner of my garage. Used (2) 46 gal Brute trash cans from HD. Top can fills with RODI water using off/on switches plumbed into side of the top Brute can. When bottom switch is activated by water getting to low switch turns ON and auto-refills until top switch is activated OFF by the water. This way my container is always full of fresh RODI. I also use this can to gravity feed my tank with a switch in my sump. Pretty cool!
Bought a used IWAKI pump on CL for $90. Works great. I only use this pump to push new SW into my house and into the tank. I plumbed pipe through my garage wall into my pantry, through another wall into my living room back behind my tank into the sump. You can hardly even notice the pipes since they're down next to the baseboards. I put 2 valves in my sump. 1 allows water through the pipes back into my tank, the other is used to pump old SW back through the same pipe outside into a water drain pipe in my front planter. The pipe has a "T" in it with valves to direct the water outside if wanted. Or, turn the valves the other way and allow the fresh new SW to push into my tank. Kind of hard to explain but it's so simple.
Here's where the plumbing goes into the house through the garage wall into my pantry:
Closer look at the valves. You can see the red handle in the back (top)... that one can direct my old SW outside into my planter drain.
My pantry is a mess! The area or wall you can see on the right under my shelves is where the main pipe enters the house/pantry and on the left you can see the pipe going through the wall into my living room:
Here's a bad shot of a small piece of pipe that entered from the pantry to my living room/ It runs along the baseboard and behind my tank stand (in the photo) and then into my sump:
Here's the shot where that same pipe comes from the left on photo above and enter into my sump. You can see how I "T'd" the pipe into 2 valves. One valve is connected to a small 1000gph pump that sits in my sump to push the old water out. The other valve is used to let fresh SW into my tank.
THIS SIMPLE MIXING STATION HAS SAVED MY BACK and LIFE! I'm loving the hobby again...no more dreading WC's !!! Questions? Ask away.