[billy08]

Hi,
I bought a Pentair prf-ro a year a go but to be honest its not been very good.
My tds is about 280, the lowest ive got out of it is 15,with  this my 7 litre resin lasts just 2/3 weeks! I use about 2500 litres of pure a week
If I dont change the pre filter every 4 weeks the tds out shoots uo to 35 which then means buying new membranes.
Would a 4040 be an improvement or would I have to look at maybe getting a water softner.
Any ideas much appreciated

[nathankaye]

What tds is from your di vessel by 2/3 wks?
I ask as many change it when it just starts to creep up. Ive cleaned windows perfectly well with pure water st 015 many a times.
 
I have a 450gpd ro and a 4.6ltr di. My tap tds is about same as yours. My di certainly lasts longer than a month. Do you compact  your resin and fill nearly to the top?
Also try a booster pump, if i use a pump it brings my tds after ro down to about 009 before it hits the resin.

[Smudger]

i used to use the older Merlin version which was excellent, however it did need a good mains booster pump as these work really well on higher water pressures  (80 psi) and i was getting a TDS of between 7 and 11 from 280 to 320


if you havent got a pump then get one and i would use a bigger di vessle also double di' ing is good practice

Darran

[billy08]

Thanks for reply Nathan, how many litres an hour does your 450 produce? Once the tds gets to about 10 I change it.
Darran my pressure is about 75 do u still reckon I need booster pump.
I've talked to Gardiners who suplied the ro about this but they've just said its possibly high calcium content or something specific with my water supply causing the problem nothing was mentioned about booster pumps

[Alex Gardiner]

Thanks for reply Nathan, how many litres an hour does your 450 produce? Once the tds gets to about 10 I change it.
Darran my pressure is about 75 do u still reckon I need booster pump.
I've talked to Gardiners who suplied the ro about this but they've just said its possibly high calcium content or something specific with my water supply causing the problem nothing was mentioned about booster pumps

Hi Billy08

If your pressure is about 75psi then fitting a booster pump would probably not improve your production or quality by much. Most booster pumps would only increase it to about 85-90psi.

At 15ppm your rejection ratio is about 94.5% which is within operating parameters of the PRF-RO unit - and is actually slightly better than our guide figures published on this RO's product pages - http://gardinerpolesystems.co.uk/all-products/pure-water-systems/water-treatment/commercial-ro-complete-systems/prf-ro-reverse-osmosis-unit.html

The problem seems to be that this 15ppm quickly reduces with use - This issue is probably down to your water input quality. At 280ppm it is fairly hard water. If a  lot of this is made up of calcium this will also affect your production quality and the performance of your membranes. If you have an old membrane to hand you can usually tell if you have high calcium content by unrolling the membrane and looking for white calcium build up. You can also ask the water board for the calcium levels in your area.

Moving forward it may be that you either need to look at a softener before the system or look at a system, like a 4040, 4021 or 3012 based system where you can flush the membranes more regularly which helps prevent calcium build-up.

I have known of a client in the past on about 300ppm where their water was so full of calcium that without a softener the membranes had clogged up within just 4 weeks.