[Simon_King]

When I started with water fed 4 years ago I had a 100gpd ro. Gave me water post RO of
4-6 PPM with a 85psi Mul pump.
Two months ago I replaced it with a 200gpd RO and fitted an RO-man  pump. This pump is self regulating and is made for residential RO systems and has a pressure of 65 - 75.
My tds from this was 28. I was not happy with this as my resin was starting to deplete after only 2 months. ( my last fill of my DI lasted 8 months)
So I figured that the RO-man pump wasnt pushing the water through the membrane at a high enough pressure so I fitted a Surflo pump 85psi. The post ro tds is now 35ppm!
WHATS GOING ON?
Should I replace the pre filters even though they are only 2 months old?
Could the two membranes be faulty?
Why the big differance in post RO ppm between old RO and this new one despite the pump on the system being the same power?
My tap water runs at 280-300ppm and has been so since I started.
I use about 650 litres of water per week.
Any help would be most appreciated.

Simon.

[Neil Williams]

The chances are that there is too much pressure over the membranes, which causes higher tds on the outlet.
1: Go back to a lower rated pump
and more important
2: The restrictor can become blocked causing higher pressure on the membranes. So either replace the restrictor or take it off and clean it through with a descaler. This does make a big difference.

Something else I have experienced is that the waste line can become blocked (remember the tds on this line will be much higher than the inlet) so check this out and renew if needed.

[L.J.Thorpe]

pretty much what neil said
i would even try it with no pump for a while
650 litres a week means you dont need the water in a hurry

[Simon_King]

Thanks for the replies.
Neil , I changed back to the RO-man pump and the ppm went down to 25. Still too high but better than the Sureflo that was pushing it out at 32 -35.
I checked the waste line and its flowing fine -full bore.
I know this sounds daft but I cant find a restrictor on this system. My old one had one but this one seems not to have one that I can see. :

L.J , tried it without any pump and the ppm went up to 35. Turned the pump on and it dropped back to 25.
I use 650litres {average} a week which isnt much compared to some on here but I do use it every day.

I think I'll change the pre filters as that could be the problem even though they are only 2 months old. Our tap water is very hard. Never changed them that soon before.
Any more ideas?

Simon

[d s windowcleaning]

i change my filters around every 2 months using the 200 gpd ro-unit but im using around 800 ltrs per day , on the ro-man pump you can turn the pressure down theres a allen key screw that you turn it shows which way to turn it for increase & decrease .

[Helen]

I know this sounds daft but I cant find a restrictor on this system. My old one had one but this one seems not to have one that I can see. :

Do you have a flush valve on your system?
If you can find that then the restrictor will be near that as both of these are on the 'waste side' of the system.

[tompoole]

where did you buy the ro? i had same problem with my 300gpd phoned purefreedom who supplied the unit and they sent out  3 new membraines tds was 38 now its 15 so seems to have cured the prob speak to andrew bradbury 1st class in my opinion

[Simon_King]

where did you buy the ro? i had same problem with my 300gpd phoned purefreedom who supplied the unit and they sent out  3 new membraines tds was 38 now its 15 so seems to have cured the prob speak to andrew bradbury 1st class in my opinion

Thanks for that. Yes its from Purefreedom. I'm local so I'll call in Monday.
Did you have an RO prior to getting your 300?

[Simon_King]

Thanks to everyone who has responded. I'll work my way through your ideas and let you know. Many thanks.

[Simon_King]

Went in to Pure freedom and explained the situation. No hassles. Replaced the membranes.
TDS post DI now 11...thats about 95-96 % pure.
When I changed the membranes I noticed the 'old' ones had ' technology derives from USA' printed on them as opposed to 'Made in USA' as on the replacements.
I think I got some poor quality membrane made in China or somewhere with my original RO otherwise why print that on the side?

Anyway all sorted now. Thanks again for all your imput.

Simon.