[cgh window cleaning]

My membrane brings the water down from around 380ppm to around 11-9ppm before D.I I am using around 1500-2000 litres a week but seem to be changing my resin every 3 weeks(11litre d.i)after 2 weeks it will start to creep.

is this about right?as I know it will very for people but a lot I read about seem to get a lot longer out there resin.
I change mine once it get to around 3-4ppm after d.i may get a month max  before change.

We're using about 1500-2000L a day

475PPM Down to 12 it was 10.

Double DI x2 15L DI's and i change the resin every 5/6 months in one of them.

I have just checked and the D.I supplied to me by pure freedom is 6.5 litres and not 11 as I thought.

Now I may be answering my own question but I'm guessing the small d.i supplied is the reason for my frequent resin changes.
After flushing out or the system has not been in use for a couple of days.I always disconnect d.i to get the water down to 11 or below before putting it through D.I. so as not to contaminate the resin I use Tulsion mb 115.

[STEVE-UK]

I never flush as advised by June at gapswater. Makes no difference she says. Same as Lee though in terms of membrane deteriation leads to less pure production not increase tds. Single hf4 u should be 70/30 waste/pure. If that is ok then prob your pressure no good

I dont flush as June gave me the same advice

[STEVE-UK]

Whether to change can depend on what it usually is After the membrane when you first install them

I know with my twin 40x40 that when new there usually about 003-007 over a year they stay about the same after the winter they will always slowly steadily climb to about 27 around end of may

I run them about 95% rejection so it's about 185-210 tds to start withso if in between 003-007 I'm happy

It varies according to time year the ratio waste to keep currently 50/50 resin will last 6-8 weeks

I supply 12 vans daily so when they hit about 19 I order new membrane

This year was better as a milder winter

You can turn the sweet spot down to produce water quicker and keep same tds reading but the membrane will need more flushing over time
The kinder you are with waste the longer they last,but you'll balance resin cost to water charges and resin usage

spot on Tony, mine are at 023, immolating at changing mine very shortly,

You have a low TDS up there, its 380 down this neck of the woods, 

is your lock up still in Uckfield? I purchased a few bits from you when you were Essentially Pure

[Perfect Windows]

I never flush as advised by June at gapswater. Makes no difference she says. Same as Lee though in terms of membrane deteriation leads to less pure production not increase tds. Single hf4 u should be 70/30 waste/pure. If that is ok then prob your pressure no good

I dont flush as June gave me the same advice

I flush every six months or so.  June told me that fould membranes don't raise output TDS, they just slow production (which makes sense - why would a bit of scale on top of a membrane blocking flow make more dissolved solids pass through themembrane?).

Since I sterilised I've had a single membrane for either three or four years and it's gone up from 8ppm out to 9ppm out.

Not sure if my earlier post mentioned it but you can tell if you have bacterial contamination if there's any element of sliminess about either the membrane or the housing when you remove it.

Vin

[rich fraser]

I never flush as advised by June at gapswater. Makes no difference she says. Same as Lee though in terms of membrane deteriation leads to less pure production not increase tds. Single hf4 u should be 70/30 waste/pure. If that is ok then prob your pressure no good

I dont flush as June gave me the same advice

I flush every six months or so.  June told me that fould membranes don't raise output TDS, they just slow production (which makes sense - why would a bit of scale on top of a membrane blocking flow make more dissolved solids pass through themembrane?).

Since I sterilised I've had a single membrane for either three or four years and it's gone up from 8ppm out to 9ppm out.

Not sure if my earlier post mentioned it but you can tell if you have bacterial contamination if there's any element of sliminess about either the membrane or the housing when you remove it.

Vin

I'm changing my membranes now. This is the only slime I can find within the housings. This is on the bottoms of the membranes.
Would this count as contamination?
I've put a weak bleach mixture into the housings to soak for now.
Does anyone know if or how long I need to soak the housings for? June from gaps did tell me on Friday to leave it an hour but I just want to double check. Last thing I want to do is destroy another two membranes!
Ideally I would leave it overnight but I need water for tomorrow.

[capn sparkle]

My membrane brings the water down from around 380ppm to around 11-9ppm before D.I I am using around 1500-2000 litres a week but seem to be changing my resin every 3 weeks(11litre d.i)after 2 weeks it will start to creep.

is this about right?as I know it will very for people but a lot I read about seem to get a lot longer out there resin.
I change mine once it get to around 3-4ppm after d.i may get a month max  before change.

Mine's almost identical to yours CGH (Hitchin based) - after 2 weeks creeps up - membrane lasted 12 to 14 months on average over last 4 yrs

[AuRavelling79]

Interesting to see the different readings.

I have found over last 15yrs 40 x 40 membraines only last about 2yrs, I have flushed them and not flushed, they still need changing after 2yrs.
A mate had found the same, 4yrs ago he was worried about legionnaires and installed a uv lamp. His membraines have now lasted 4yrs without any drop in production or water quality.
On changing my membraines in March, I now have twin 21 x 40, I put in a uv lamp, cost £130.
I will see in 2yrs what the results are.

Just noticed this post, Roy - sorry for late pick up ... UV lamp?