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adamangler

R.O problem - can you bleach them out ?



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adamangler
Posted (edited)

Hi chaps.

 

Having a problem with my 450 gpd r.o that the tds wont go down on.

 

About a year ago i upgraded from a 150 to 450 r.o put new membranes in all was fine.

 

Anyway about 3 months ago tds was getting up to about 40 so i ordered some cheap membranes off ebay and sediment and carbon filters. Changed it all over but the tds was about the same, around 30-40. I was a bit gutted and put it down to the cheap membranes (voltron).

 

So fast forward to last week and the tds had gone up to 50...so i ordered some axeon membranes from @doug atkinson they came today...i put them in with new sediment and carbon filter, flushed it, ran it for a bit etc....tds wouldnt come down below 50

 

so now im a bit perplexed, i checked each membrane one by one by by-passing the others to see if one was the problem.... nope. i took the carbon and sediment filters out, nope still same.

 

I noticed when i by passed the last resin cartiridge the tds dropped slightly, but the resin chamber is empty and all clean inside.

 

SO i took each mebrane and housing off and run it direct to the outside tap and after a quick run they were coming out at 12 tds (from 280 tap)

 

put them all back on the r.o and tds back up to about 50.....

 

SO (lol) the only thing i can think of is the housings, pipes etc are contaminated ? is this possible to affect tds like this ? if so how do i clean it, run a load of bleach through ? any other ideas anyone ?

 

@spruce any ideas ? 

 

thanks

 

Edited by adamangler

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AGlassAct

Some membranes need AT LEAST a couple of hours to settle. Give them chance to bed in and see what the TDS is then. I’ve never heard of housings getting contaminated to the extremes your talking about but I did read on one of my pre filter housings they recommend you renew the ‘bowl’ portion every two years - so it must happen. Doug will have the answer I’m sure!!


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adamangler

Ive bought 2 lots of membranes now and had the same thing, both times when changed the tds is about 30-50 even after days/weeks

 

never had this before, just wondered if its getting old, if cleaning it doesnt work ill have to buy a complete new one 

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doug atkinson

Hold the pure and the waste water pipes side by side. Does the waste water flow longer than the pure water?

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adamangler
4 minutes ago, doug atkinson said:

Hold the pure and the waste water pipes side by side. Does the waste water flow longer than the pure water?

 

ive played around with the pure waste ratio doug, i use a tap to alter the ratio, it doesnt seem to make a difference.  i had it set at 50/50 when my tap tds was 150, now i have it set at 70 waste 30 pure, but ive tried all sorts of ratios and the same i cant get it below about 30 at best

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doug atkinson

Okay try and measure each membrane what the output ppm is. You probably may have some contamination somewhere. measure the ppm after filters.

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Iron Giant

Have you also changed your pre-filters for good quality ones as the cheap membranes will have had a negative impact on the pre-filters, I had R/O issues a while back and new membranes and new pre-filters did the trick.

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adamangler

There must be something contaminated somewhere as as a last resort i have taken 1 membrane and housing off and connected it straight to outside tap, set the pure/waste to about 60/40 with a tap on the waste outlet and im getting 16 tds (3 months old voltron membrane)

 

i will use it like this until the weekend then strip the whole thing down and check pure tds after each membrane etc.

 

thanks for your help

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Skxawng

I don't know any normal reason why the readings should be that high. The only thing I can think of is that you may have mixed up the output pipes on one of the membranes (I assume you have 3) so the waste from one is going to join the pure from the other two membranes and the pure output is going to the waste.

 

I've a similar problem but not as extreme- Just bought 3 new Axeon membranes and after a day of running they're producing 13ppm with 313 input. That's only 95.8% which is disappointing seen as they're supposed to be 98%.

 

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doug atkinson

What I have noticed recently with Axeon membranes it’s taking a lot longer to get our test results. Could normally achieve it in 2/3 hours now it’s taking around 10/12 continuous flushing.

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