Issue with my 450gpd RO

Hi guys starting to tear my hair out with my 450gdp RO this morning and need some advice.

brought the system from @doug atkinsonat Daqua and it's been fine for past six months or so, with a booster pump attached it provides a good amount of pure which goes into a 11 litre DI vessel. My starting water is 252

Recently my water has been going up and now sits at 004 from the Di. I've replaced the pre filters last week but I replaced the resin over six weeks ago. My theory is my original pre filters were badly damaged but thinking the resin was ruined I changed that first when I should have done the prefilters, so that's battered my resin and I'll have to buy in new.

my other concern is the other filters on the top of the unit (the white tubes mounted on top of the RO system), would these be the culprit, do they now need changing too? I'm not even sure what there called.

any advice would be great as I'm getting hair off with it now, just want my pure water back and stop wasting money.

Hi, just to get the facts straight.

Your water supply has 252ppm tds.

Your output is 4ppm. That's over 98% rejection rate which is good. It seems like the Ro system is working fine but the resin needs changing. If the resin were fine you would be getting 0ppm.

Just to bear in mind, when you change the prefilters you have to discard the first (few hundred? Maybe someone can correct me) Litres of water as the carbon filters have preservative and other things in them. If they were connected to the rest of your setup then they will have reduced the life of your resin and that would explain why the resin has gone quicker than you thought it would. Also it's not good for the RO membranes either to have the new prefilters flushing through them.

Otherwise 4ppm is pretty good.

What is the water before DI, after R/O? Check your input TDS, then check TDS after R/O. This will tell you how well your Membrane is working 

Yes starting water is 252, after RO and DI it's 004 @Skxawng. I'm unsure on the preservatives in prefilters not heard that before but you may well be right. As you say would explain the jump in impurities if it ruined the resin.

so am I correct in thinking when you run them for x amount of time before connecting to the DI? If so I've shot myself in the foot.

ill have to check the tds after RO but before DI @Part Timer and get back to you. I know when I first brought the unit my starting water was at 330 ppm, after RO (no DI attached) it was 008! Which I thought was pretty good for basic filtration. With my starting water no lower (dropping from 330 to 252) everything would last longer making my life easier not harder!

so frustrating!!

@Part Timer

Starting water 252ppm

after RO 038ppm

after RO and DI 004ppm

think the resin is ruined, shouldn't struggle with 038 much should it being a 11 litre vessel ?  

The R/O isn't working properly, probably the membrane is shot. It should be getting it down to below 10, closer to 5 really. 

Cheers @Part Timer so the membrane Is the white tubes after the pre filters on a 450 system? I've tried to unscrew one of those already but there's fitted pretty tight. 

Yes when I got the system it was 008 after RO so it's gone up a lot 

Once they are replaced will the resin still be shot?  

@doug atkinson could you link me to those membranes please?

Your asking for advice providing incomplete information, How much pure have you produced in the last Six weeks if its 2500Litres a week @ 38ppm then yes your 11lt of resin will be shot and will need replacing, if a lot less then I would suspect the membranes need replacing or even are not fitting correctly and alowing tap water to bypass them, I would invest in Three 150 L mebranes from a reputable source before doing anything else.

Philip Hardy said:

Your asking for advice providing incomplete information, How much pure have you produced in the last Six weeks if its 2500Litres a week @ 38ppm then yes your 11lt of resin will be shot and will need replacing, if a lot less then I would suspect the membranes need replacing or even are not fitting correctly and alowing tap water to bypass them, I would invest in Three 150 L mebranes from a reputable source before doing anything else.

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Hi Phil

im probably using/producing about 1000 litres at most per week. I too would suspect that the resin will need replacing but prior to that the membranes as the pre filters are brand new. Contacted Daqua for the right membranes and will get those up and running asap.

ive got enough water for the week but 004 is higher than I'd like, thankfully this is a quieter week.

Ana said:

Hi Phil

im probably using/producing about 1000 litres at most per week. I too would suspect that the resin will need replacing but prior to that the membranes as the pre filters are brand new. Contacted Daqua for the right membranes and will get those up and running asap.

ive got enough water for the week but 004 is higher than I'd like, thankfully this is a quieter week.

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You will get by with 004 as some use pure up to 10ppm without problems, Daqua will supply you quickly so you will only have to worry if its stll 38ppm after the new membranes are fitted, as this could show a leakage inside the membrane housing,I would order some new resin in now as well as you will always need it, it keeps well. so if you dont have to use it quickly, its on stock for you.

Thanks phil 

ill buy in both as a precaution anyway.

ive been using 001/002 for the past couple of weeks no issue, so I'd doubt 004 is going to have much baring on much. 

Just a clarification, earlier I wrote that the carbon filters have preservative but I was thinking of the RO membranes. It's still recommended to flush the new prefilters before connecting the output to the RO membranes. Not sure why, probably to flush out debris that could damage the delicate membranes. 

I'm surprised your membranes are performing so badly at 6 months old. They usually last years..

Ana said:

Cheers @Part Timer so the membrane Is the white tubes after the pre filters on a 450 system? I've tried to unscrew one of those already but there's fitted pretty tight. 

Yes when I got the system it was 008 after RO so it's gone up a lot 

Once they are replaced will the resin still be shot?  

@doug atkinson could you link me to those membranes please?

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https://www.daqua.co.uk/reverseosmosis.htm.    Have you had any burst pipes dirty water as this clogs up the membranes 

doug atkinson said:

https://www.daqua.co.uk/reverseosmosis.htm.    Have you had any burst pipes dirty water as this clogs up the membranes 

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Thanks doug I'll look to grab some later this coming week. No, nothing like that as far as I'm aware and I'd know haha.

Skxawng said:

Just a clarification, earlier I wrote that the carbon filters have preservative but I was thinking of the RO membranes. It's still recommended to flush the new prefilters before connecting the output to the RO membranes. Not sure why, probably to flush out debris that could damage the delicate membranes. 

I'm surprised your membranes are performing so badly at 6 months old. They usually last years..

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Me too but I'll order some anyway, i have to try and get the numbers down. I'll give it a good flush and see what the numbers come out at.

as I've stated before when I began to use the system (some six months ago) my starting water was at 330ppm, after RO it was at 008ppm. My starting water now is 252ppm so the system should be having a easier time of it.