This is just my opinion but after years of operation you are going to have to service or clean the pvc plumbing. When I set up my tank I only put union ball valves or union valves in specific areas, such as around the return pump or before the sump etc., [not thinking ahead]. 7 years later the return water flow was cut to around a quarter. I had to cut my pvc pipes at several points since it was clogged with growth over the years, see attached pic. While you are still in the planning stages you should consider that if you haven't already done so. It'll save you a headache later on.So I got my plumbing done today for the drains and returns. I went with regular white schedule 40 pvc. Three trips to Home Depot today alone and quite a few cuts and recuts. The drains are 1.5” and the returns are 3/4” from the tank manufacturer. So I had to reduce the L2 lines from 1.25” down to 3/4”. I used 3/4” George Fisher wye check valves on the returns up towards the tank. Started putting my RODI online but I need long lengths of tubing for my new configuration. Ordered 100’ from marine depot. I have a cesspool at my new house so I can’t run my waste water into it. So I will run the waste water line out of my house into the driveway for now. Considering putting in a drywell down the road. I will be ordering a 125 gallon reservoir from tank depot. Going with a horizontal configuration based on the space. If anyone has one for sale hit me up. Or knows a place locally that has them in stock I’d appreciate the reference. The store on sunrise highway is closed. I will run my ATO from my reservoir and I have the dual float switch controller from AquaFX.