[rich fraser]

I fitted new twin hf4 membranes February 16. My tds is now up to 45 ppm and I'm having to refill di vessel every 2/3 weeks. I'm filling 3 vans daily.
Do I continue refilling resin or buy new membranes?

[Lee Pryor]

thats not long. Do you flush properly? By properly I mean 20-30 min 3-4 times a week, not 5 min once in a blue moon. Do you use a softner?

It may be your waste isnt open enough that can raise TDS. Try letting a bit more down the drain.

I tend to find that when they ware out the TDS can stay low but the production speed really drops.

If you do change go for HF5 next time.

[jk999]

What size di do you use

[rich fraser]

thats not long. Do you flush properly? By properly I mean 20-30 min 3-4 times a week, not 5 min once in a blue moon. Do you use a softner?

It may be your waste isnt open enough that can raise TDS. Try letting a bit more down the drain.

I tend to find that when they ware out the TDS can stay low but the production speed really drops.

If you do change go for HF5 next time.

I'm boosting the water pressure in and think that's why I went with hf4. That was the advice from gaps water I think.

Inlet tds is 335ppm.

Have tried to increase waste flow but no improvement.

Flush for 10 minutes with booster off before almost every fill of 100L ibc.

Not sure how fast its producing as its got auto shut off, I just leave it to it.

I'm just not sure which way will be most cost effective. Resin or membrane?

[rich fraser]

What size di do you use

I use a single 25 Litre di

[Rogue Trader]

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

[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 have no idea why in happens but my waste/pure ratio has always been around 50/50. It seems to be the tds sweet spot for this set up.

[Mick Kent]

i use a single hf5 unboosted as have good pressure at yard which takes water to 006ppm from 360ppm in, i change filters every 2 months and flush once a month for a few hours from filling 4 x 1000litre ibc's, i sell water to 4 guys as well as myself and a membrane  lasts me 6-8 months before creeping upto 20ppm which is when i get a new 1, i'm more than happy with how much water i get per membrane.

[Tony dunmall]

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

[andyM]

I fitted new twin hf4 membranes February 16. My tds is now up to 45 ppm and I'm having to refill di vessel every 2/3 weeks. I'm filling 3 vans daily.
Do I continue refilling resin or buy new membranes?

Have you changed the pre-filter/s since February 16?

[Clever Forum Name]

It needs replacing or the issue sorting out, i think more waste is needed personally. I think you may have burnt holes in the membrane.

https://www.hamzasreef.com/Contents/Calculators/RORejectionRate.php

[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.

[Shrek]

I bought my 400gpd from vyair in November, before RO it was 270 , after it was about 3 to start off with.
Now it's 10 after RO , I use about 2000 ltrs a week with an 11ltr vessel and changed it once so far .

I am a bit concerned that it's gone to 10 after RO in 6 months....

Sam at vyair said I need to flush it once a day with the valve fully open and then produce with the valve fully closed- non of this 50/50 or 60/40 

[andyM]

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.

My 4040 produces output at around 9ppm.
I will change resin when it rises from 0ppm to about 3-4ppm.
An 11 ltr vessel of Tulsion mb115 lasts me a year.   

[Roy Harding]

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.

[Spruce]

My HF5 4040 membrane is 5 years old in July. No booster pump and its still producing water at the same rejection rate as when it was new. Our water tds varies between 99 and 125ppm although I see the water is 87 this morning and the r/o is producing at a rejection rate of 1ppm. (The water board flushed the pipes just over a week ago. I had the r/o switched off when they were doing it.)

I change the 7 liter di vessel once a year, probably because I don't worry too much about tds creep.

[Spruce]

I fitted new twin hf4 membranes February 16. My tds is now up to 45 ppm and I'm having to refill di vessel every 2/3 weeks. I'm filling 3 vans daily.
Do I continue refilling resin or buy new membranes?

I would test the rejection rate of each membrane first.
If one is fine and the other not then you have your answer. If they are both faulty then the issue is chlorine contamination or you have a bug in the system.

It could also be that you have a bug in your r/o housing. Vin from Perfect Windows in Southampton had that issue although he didn't need to produce as much water as you do.  The solved it with a bleach mix and replacing the membranes. He also changed the c/block and uses a di vessel filled with acid washed charcoal I think it is. He made a post on here about 5 or 6 years ago detailing his troubles. June from GAPS was involved in the solution.

Lets guess. Filling 3 x 650 liter tanks a day = 2000 liters. At a 50/50 pure to waste ratio you will be using 4000 liter per day. Over 5 days that 20000 and over a month is about 85,000 liters.

If you are using a Fiberdyne carbon block then it should be replaced at least once a month if you follow the manufacturers guidelines. A GAC filter needs to be replaced every 10,000 liters; that's every 2 and a half days.

.

[Perfect Windows]

Here's my post on clearing contamination (which it sound like to me).  Hope it helps.  What I suspect also helps is having a 4-way splitter on my wall tap so I never have to disconnect the hose from the water - less opportunity for contamination.

http://www.cleanitup.co.uk/smf/index.php?topic=159299.msg1322877#msg1322877

Vin

[Spruce]

Here's my post on clearing contamination (which it sound like to me).  Hope it helps.  What I suspect also helps is having a 4-way splitter on my wall tap so I never have to disconnect the hose from the water - less opportunity for contamination.

http://www.cleanitup.co.uk/smf/index.php?topic=159299.msg1322877#msg1322877

Vin

Thanks Vin.

[Clever Forum Name]

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.