Spruce what reading would you expect after the ro with my reading before of 70, I have recently been filling my van up at the end of the garden hence running a hose about 50 ft maybe it’s the water pressure, I’m happy using water that’s got a reading of 1 but why does it get it down from17 before to 1 and not o
What r/o have you got?
It sounds to me that you have an on board unit so I'm thinking its a 4040 or 4021.
If this assumption is correct then you need to get rid of your supply hose. Microbore isn't good enough to supply the needs of your r/o.
Your supply at the end of the hose needs to deliver around 9 liters of water per minute for a 4040 to work. That microbore will be restricting the water to the r/o and will be reducing the water pressure on the membranes exacerbated by your 3 to 1 waste to pure ratio.
With your low input tds you could well run at a waste to pure ratio of 55 to 45 or even 50 to 50. This may mean replacing your waste restictor to on that will allow fine adjustment.
If your membrane was working efficiently then you should expect a rejection rate of 97 to 98%.
At the moment your resin is polishing off the high remaining tds. The reason why its not getting to zero is that it probably spent and the tds will rise. If you have just replaced the resin then the di vessel could be faulty, or your resin is suspect or your tds meter might be reading wrong.
Unfortunately we need more info to help you. Hence the reason for all those questions.
