[mac74]

Hello, what TDS do you fella's change your membrane at? i.e the best balance between membrane and resin costs? Thanks m

[Smudger]

018


Darran

[mac74]

018


Darran

Really that low?
When i put i new one in it comes out at around 10/12ppm,  and wait until it hits about 028.

[Smudger]

I don't use resin anymore

when I did I found the volume I produced meant I would kill a complete bag of resin in 7 to 10 days and at £80 a bag it makes more sense to dump a membrane and start again

I goto 012 - then descale the membrane - that returns it to 006/007 for about 2 weeks then I replace with a new one

Darran

[Spruce]

Hello, what TDS do you fella's change your membrane at? i.e the best balance between membrane and resin costs? Thanks m

It depends on your input tap water tds and the amount of water you use.

There is no specific recommendation as it will depend on your particular circumstances.

For example, a supplier once told me that you would start to consider changing a membrane when its rejection rate was 94%. (At the time our tap water tds was 254ppm.)

So the tds of your tap water is an important consideration. If you are in a soft to medium hardness area you might wait a little longer as a small increase in pure water tds isn't going to make much difference to the cost of resin to polish those off. The same would apply if you don't process much water.

If you filter a lot of water then you might have to consider an earlier change. It's all down to your business' 'economies of scale' which will be different to other cleaners.

[Spruce]

018


Darran

Really that low?
When i put i new one in it comes out at around 10/12ppm,  and wait until it hits about 028.

I think it also depends on your water whether you use resin or not.
The same supplier who told me that the cutoff for membrane replacement was a rejection rate of around 94% also stated that pure at 4ppm didn't need to be polished off with resin.
I did a test and found tiny spots on our lounge window in the low morning sun at 5ppm. A customer would never notice them. At 10ppm the white spots were clearly noticeable. So when the pure after resin reaches 1ppm I plan a day when I will change the resin in my di vessel.
I did leave it once and found the tds took a long time to reach 2 and then 3. It suddenly  jumped up to 5 and 6 very quickly.

[Granny]

I don't use resin anymore

when I did I found the volume I produced meant I would kill a complete bag of resin in 7 to 10 days and at £80 a bag it makes more sense to dump a membrane and start again

I goto 012 - then descale the membrane - that returns it to 006/007 for about 2 weeks then I replace with a new one

Darran

How do you descale the membrane I am getting an RO when I move and that would be good to know as I'm a newbie RO user.

[Smudger]

I have a soil pipe slightly longer than the membrane and slide it in there with sore pure and 1/2 bottle of kilrock descaler
leave for 24 hrs then put back into the housing and flush for 1/2 hour

Darran

[Granny]

Ta I've got a lot to learn!

[mac74]

My input TDS is 420ppm  . I also tried the descaling thing, but for the sake of a few fill ups, i didn't think it was worth the hassle tbh. I took the top end off the ro unit, and filled it up with the descaler mix upright in its own housing, and blocked the bottom end off.
Thanks m

[CleanClear]

I goto 012 - then descale the membrane - that returns it to 006/007 for about 2 weeks then I replace with a new one

What makes you think its scale on the membrane. And when you flush it out after using the descaler, what comes out in the waste water , what does it look like?

[Smudger]

After the descale the water coming out is usually milky and a bit frothy for 10 to 15 mins then over the next 15 mins goes clear - TDS is vastly improved but the effect is quite short term - but longer and cheaper than a bag of resin

Is it scale ? - don’t know but it breaks down or loosens the crud in the membrane

Darran

[CleanClear]

After the descale the water coming out is usually milky and a bit frothy for 10 to 15 mins then over the next 15 mins goes clear - TDS is vastly improved but the effect is quite short term - but longer and cheaper than a bag of resin

Is it scale ? - don’t know but it breaks down or loosens the crud in the membrane

Darran

When you take the membrane out, does it feel all slimey?

[Smudger]

No

Darran