4 Stage Reverse Osmosis System

[Skean Dhude]

I would filter all water as much as you can via a cloth as it saves on the expensive and hard to replace filters in your system. The more you can filter, via sand, cloth, etc. the longer your system will last.

Plus Milton can attach the membranes on filters and enlarge the holes, invisible to our view, that allows the bad stuff through. I wouldn't add any either.

These systems are heavily used in the marine area on boats. They don't all need external power but the throughput is much lower. However, in the end it is a single sheet of plastic membrane with microscopic holes. A rip, tear, enlarged holes and it is useless.