I wanted to add reverse osmosis to my trilogy. I had decided to add it only to the refrigerator. After dropping the bottom cover I discovered how easy it would be to run it to the kitchen island so I added the faucet for cooking water. I plumbed the waste back to the fresh water tank to not fill up my grey water tank. I plan to use my fresh water tank to keep the pump working good. I will also modify my system by adding a valve between the supply and waste so I can fill my fresh water tank without messing with hoses and tubing. I took the supply from the tubing to the refrigerator.
This seems like quite the setup you have here. I have never seen it being done like this before with any water filter, let along a reverse osmosis system. But I don't understand why you are pumping the waste water into your fresh water tank. Doesn't that defeat the purpose of using a reverse osmosis system.
Dumping the RO waste into the fresh water tank will work. Many commercial RO systems recycle a percentage of waste back through the system to reduce water usage. An RO system like the one pictured can use 3 gallons to make one. I would expect your pump to run a lot until the storage tank of the RO fills.
2016 Cedar Creek 36ckts
2015 Ford F-350
4WD SRW Diesel
My current pump is not for use with to systems. There a ways to make your ro more efficient such as a high pressure pump, high pressure relief valve and a permeate pump. My plan is to use water from the tank I will refill as needed. This will dilute the water in the tank. You can actually run the water through multiple timed. Some systems run it through up to 6 membranes. I will add a second membrane to my system.