Welcome to the UK Window Cleaning Forums

Starting or own a window cleaning business? We're a network of window cleaners sharing advice, tips & experience. Rounds for sale & more. Join us today!

Ro problem

Dave85

Member
Messages
98
Location
North yorkshire
HI just a quick question regarding my ro system.

My system is a 450 gpd unit that is only a month old and I'm all ready having issues. My tap tds is 395ish and once tap water has gone through pre filters and membranes it's around 030ish then goes through resin and comes out at between 001 and 003.all seems good however my resin is only lasting literally a day or 2.I changed my resin lastnight and was getting 000ppm  (brand new telusion resin ) and I'm now getting 005 and 010 ppm tonight ? I have even fitted a booster pump as my tap pressure is just below 40 psi. But added water pressure isn't really helping.I'm out of ideas of how to resolve this issue as I have had to do countless resin changes recently and pretty fed with it now so any ideas or help is much appreciated. 

20170829_184158.jpg

 
Your di is way too small

You will be changing it daily with one of those 10" housings as a vessel

You need a proper 11 litre or bigger di vessel to be effective 

Your tds should be 12ppm max ideally from ro.. 30 is way too high for a new ro

 
I thought 30 ppm after pre filters and membranes was high. I do flush the ro weekly .what would be the solution to a lower tds before di. Without spending more money idealy,

Thanks

 
I thought 30 ppm after pre filters and membranes was high. I do flush the ro weekly .what would be the solution to a lower tds before di. Without spending more money idealy,

Thanks


It might have something to do with the quality of the membranes Collins Water Products sell.

Cleaners always seem to get locked into buying at the cheapest price. In wfp, that doesn't always result in a good performance.

CWP use a Chinese manufacturered membrane which isn't as good as the US manufacturered ones.

Sometimes saving a few pennies initially can prove to be costly further down the line.

ATM your membranes are performing at around 92%, which is already in replacement territory. Low water pressure isn't a help either as their membranes are better at 65psi if memory serves me.

 
Last edited by a moderator:
OK thanks for advice spruce . And if I was to test the output of each membrane separately what would be the ideal ppm from each one.BTW you should start charging for your ro advice on here! ?

 
Ahh ok I have heard that collinswater membranes are bad quality. Unfortunately found this out after I had purchased and fitied the ro system.


Unfortunately the amount you saved buying the unit will be quickly spent on resin to polish the high tds off. 94% rejection rate was considered to be the cutoff with reasonably soft to medium water. Your cutoff point could be higher; ie 95 - 96% as your tap water tds is much higher. Sorry, but I haven't done the maths to find that cutoff point.

The first thing to do is the check the pure output tds of each membrane incase you have a rogue one. Also make sure that they are all connected up right - in other words you haven't a waste connected up to the pure output side.

What is your pure to waste ratio?

If everything is in order then the quicker you replace those membranes with better quality ones, the sooner you will reduce your resin costs and save money.

.

 
Last edited by a moderator:
OK thanks for advice spruce . And if I was to test the output of each membrane separately what would be the ideal ppm from each one.BTW you should start charging for your ro advice on here! ?


Ideally you will be looking at around 97% for those membranes which is what Daqua suggested a few months back on another post. I doubt whether those CWP membranes will achieve 95% - 96% even when new and just bedded in. But the incoming water pressure is also very important.

 
Ideally you will be looking at around 97% for those membranes which is what Daqua suggested a few months back on another post. I doubt whether those CWP membranes will achieve 95% - 96% even when new and just bedded in. But the incoming water pressure is also very important.
Quick update .i have just fitted new pre filters and new aexon membranes gave them a good flush out and still getting a tds reading before di off around 28ish .how long do new  membranes take to bed in .

Thanks 

 
Back
Top