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RO Output Help

P4dstar

Premium Member
Messages
3,594
Location
Gloucestershire
My RO is 4 years old. I've just changed the membrane for the first time. I got a replacement HF5 membrane from Doug @ Daqua. There are no directional arrows so I have assumed the writing should be written following the directional arrow on the cylinder. We tightened the clamps nice and tight to maintain the pressure and set it all back up.

Prior to changing I had....

60psi after booster
input TDS of 335
Output TDS of 28-32
Ratio 55:45

After the change I have....
60psi after booster
input TDS of 335
Output TDS of 25-26
Ratio 55:45

First things first, is there anything I can have done wrong?

Second problem. We run double DI. Changed the resin maybe 3 and a half weeks ago and it needed changing again today. I would estimate we used 750L on average each day. I know the output TDS has been high but that seemed a little quick to have to change a 15 litre vessel.
 

Pjj

Premium Member
Messages
11,150
Location
Cornwall
I think @doug atkinson is the best one to answer this one, but believe if producing that much per day most would use twin ros ? Output TDS seams very high to me , but ime used to lower numbers than yours ,apart from when working away from home then we dump a lot more water
 

P4dstar

Premium Member
Messages
3,594
Location
Gloucestershire
I think @doug atkinson is the best one to answer this one, but believe if producing that much per day most would use twin ros ? Output TDS seams very high to me , but ime used to lower numbers than yours ,apart from when working away from home then we dump a lot more water
I’ve never understood the twin RO thing but it produces 200 litres an hour.
How long did you flush it for? A new membrane could take a few weeks to get to its most efficient point.
Flushed it for around 2 hours before I used it mate. It’s a long time since I originally set it up and back then Doug sent it to me tested and ready.
 

scottish cleaning service

Well-known member
Messages
7,491
Location
Paisley
My RO is 4 years old. I've just changed the membrane for the first time. I got a replacement HF5 membrane from Doug @ Daqua. There are no directional arrows so I have assumed the writing should be written following the directional arrow on the cylinder. We tightened the clamps nice and tight to maintain the pressure and set it all back up.

Prior to changing I had....

60psi after booster
input TDS of 335
Output TDS of 28-32
Ratio 55:45

After the change I have....
60psi after booster
input TDS of 335
Output TDS of 25-26
Ratio 55:45

First things first, is there anything I can have done wrong?

Second problem. We run double DI. Changed the resin maybe 3 and a half weeks ago and it needed changing again today. I would estimate we used 750L on average each day. I know the output TDS has been high but that seemed a little quick to have to change a 15 litre vessel.
Should the pressure not be 80 to 100 ? Doug will answer that question.
 

spruce

The Sprucefather
Messages
8,003
Location
Teesside
My RO is 4 years old. I've just changed the membrane for the first time. I got a replacement HF5 membrane from Doug @ Daqua. There are no directional arrows so I have assumed the writing should be written following the directional arrow on the cylinder. We tightened the clamps nice and tight to maintain the pressure and set it all back up.

Prior to changing I had....

60psi after booster
input TDS of 335
Output TDS of 28-32
Ratio 55:45

After the change I have....
60psi after booster
input TDS of 335
Output TDS of 25-26
Ratio 55:45

First things first, is there anything I can have done wrong?

Second problem. We run double DI. Changed the resin maybe 3 and a half weeks ago and it needed changing again today. I would estimate we used 750L on average each day. I know the output TDS has been high but that seemed a little quick to have to change a 15 litre vessel.
These instructions are for the Champ housing, but fitting the membrane correctly is the same.
 

Attachments

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Pjj

Premium Member
Messages
11,150
Location
Cornwall
I’ve never understood the twin RO thing but it produces 200 litres an hour.

Flushed it for around 2 hours before I used it mate. It’s a long time since I originally set it up and back then Doug sent it to me tested and ready.
I don’t fully understand it either😂😂😂 but it produces a larger quantity of water faster , with my set up and booster pump with a tap TDS of around 100 I can produce 1000 ltr of pure in 2 hours
 

doug atkinson

Well-known member
Messages
1,338
Location
Fife
There would have been instructions in the documents enclosed envelope how the membrane is changed.

The “o” ring on the membrane should be seated on the entry side from pre-filters. So the waste/pure cap should be secured to the housing then insert the membrane in with the “o” ring the last to go in. Then use a screw driver and insert into the shaft and gently knock in with a hammer so the membrane is seated on properly.

Then secure the other end cap.

When first starting up the system you get a rejection rate of around 92% as the membrane is coated in chemicals.

I am finding that it now takes around 17 hours of flush to get rejection rate of 97/98%.

But that’s a lot of water so flush for couple of hours and if you happy with the ppm it will settle in 2/3 weeks with constant production.

How many litres per minute are you getting.
 

P4dstar

Premium Member
Messages
3,594
Location
Gloucestershire
These instructions are for the Champ housing, but fitting the membrane correctly is the same.
Thanks Spruce
I don’t fully understand it either😂😂😂 but it produces a larger quantity of water faster , with my set up and booster pump with a tap TDS of around 100 I can produce 1000 ltr of pure in 2 hours
So have you literally got 2x 4040 RO membranes running simultaneously?
 

P4dstar

Premium Member
Messages
3,594
Location
Gloucestershire
There would have been instructions in the documents enclosed envelope how the membrane is changed.

The “o” ring on the membrane should be seated on the entry side from pre-filters. So the waste/pure cap should be secured to the housing then insert the membrane in with the “o” ring the last to go in. Then use a screw driver and insert into the shaft and gently knock in with a hammer so the membrane is seated on properly.

Then secure the other end cap.

When first starting up the system you get a rejection rate of around 92% as the membrane is coated in chemicals.

I am finding that it now takes around 17 hours of flush to get rejection rate of 97/98%.

But that’s a lot of water so flush for couple of hours and if you happy with the ppm it will settle in 2/3 weeks with constant production.

How many litres per minute are you getting.
Thanks Doug. I'll be honest the documents enclosed thing is lost somewhere in the mess that is my garage.

Checked everything and it's all in correct. I didn't even spot that O ring. Its currently down to 20 TDS from 363 so nearly up to 95%

Looks like I'm producing 4 litres a minute on a 55/45 ratio. I'm reluctant to lower that to 60/40 because the PSI drops as I open the tap and I don't seem to get a better output TDS.
 

Bob1980

New member
Messages
18
I apologise for spamming your thread but I've been looking at a 40 / 40 system. My tds pre membrane is 245ppm and water pressure is 80 psi.

Roughly how long would I be able to produce without changing the filter.

I produce around 2000 litres per week Roughly.

Thanks and sorry once again
 

P4dstar

Premium Member
Messages
3,594
Location
Gloucestershire
I apologise for spamming your thread but I've been looking at a 40 / 40 system. My tds pre membrane is 245ppm and water pressure is 80 psi.

Roughly how long would I be able to produce without changing the filter.

I produce around 2000 litres per week Roughly.

Thanks and sorry once again
Spam away mate. I have a water meter on my system, The 20" pre filters are changed just as recommended so every 25k litres for the sediment and every 75k for the carbon.
 

spruce

The Sprucefather
Messages
8,003
Location
Teesside
Thanks Doug. I'll be honest the documents enclosed thing is lost somewhere in the mess that is my garage.

Checked everything and it's all in correct. I didn't even spot that O ring. Its currently down to 20 TDS from 363 so nearly up to 95%

Looks like I'm producing 4 litres a minute on a 55/45 ratio. I'm reluctant to lower that to 60/40 because the PSI drops as I open the tap and I don't seem to get a better output TDS.
You've found the r/o's sweet spot where it working at it most efficient between waste to our ratio and water pressure.
 

spruce

The Sprucefather
Messages
8,003
Location
Teesside
Thank you and what about the membraine
You change the membrane when it's rejection rate (efficiency) drops.
You judge that by how pure the water leaving your r/o is.

When a membrane is new and settled in you should expect around a 98% rejection rate. So if your tap water is 100ppm then this means the pure from your r/o would be 2ppm. (Your resin will polish off those 2ppm.)

The rule of thumb was when the rejection rate dropped to 94% (6ppm pure from your r/o) was when to consider changing your membrane.

There are a few things to consider: the high cost of resin, your tap water tds and the high cost of water if you are on a metre and of course the cost of the replacement membrane. So you may consider to change it a little earlier or even a little later according to your circumstances.

My axeon Hf5 membrane isn't cheap to buy, but then its still producing at 97% and 10 years old. The trick that works for me is for membrane longevity is to change prefilters to the manufacturers specifications.
 

Pjj

Premium Member
Messages
11,150
Location
Cornwall
From one input? How many ore pre-filters? does the output water rejoin into one line? I'm open to the suggestion of this idea
Yes one input from tap it goes through 2x10 inch pre filters before the van then the carbon sediment, 5 micron, water softener then the two ro hears a picture excuse all the junk on the tos 😂😂😂
 

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Bob1980

New member
Messages
18
You change the membrane when it's rejection rate (efficiency) drops.
You judge that by how pure the water leaving your r/o is.

When a membrane is new and settled in you should expect around a 98% rejection rate. So if your tap water is 100ppm then this means the pure from your r/o would be 2ppm. (Your resin will polish off those 2ppm.)

The rule of thumb was when the rejection rate dropped to 94% (6ppm pure from your r/o) was when to consider changing your membrane.

There are a few things to consider: the high cost of resin, your tap water tds and the high cost of water if you are on a metre and of course the cost of the replacement membrane. So you may consider to change it a little earlier or even a little later according to your circumstances.

My axeon Hf5 membrane isn't cheap to buy, but then its still producing at 97% and 10 years old. The trick that works for me is for membrane longevity is to change prefilters to the manufacturers specifications.
Thanks spruce you are a legend of this forum agreat read with full detail in. Thank you.

What is the tds of your water before the ro set up?
 
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