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Jango

Puzzled by tds reading.

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Jango

Right guys, I've given my ro setup a good flush out for a few hours, I usually flush it 15 minutes a day when I fill up my tank in the van from the Ibc. 

So this morning I've been checking the levels. My water flows in at 60psi, I don't have a booster pump. 

So my tap TDS Is 282. It then goes through sediment and carbon filters coming out at 286?????

then through membrane coming out at 11 TDS, through resin vessel coming out at 2. 

The carbon/sed were changed a couple of months ago. I use maybe 2000 litres per week. Any help please? 

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Kleenwell

Have to calibrated you tds meter recently?

 

higher TDS after carbon filter could be a dodgy cartridge.

what gpd is your membrane?

Edited by Kleenwell

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Nudel

Maybe I've misunderstood, but aren't the purpose of the prefilters to remove large bits/gunk and water additives than can damage the RO membrane, not lower the TDS readings?

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steve garwood
1 hour ago, Nudel said:

Maybe I've misunderstood, but aren't the purpose of the prefilters to remove large bits/gunk and water additives than can damage the RO membrane, not lower the TDS readings?

That is correct. Pre filters don’t lower the TDS 👌

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Jango

Ok . So why would my tds be higher than my tap tds after the two pre-filters, that's what's puzzling me, could you explain it to me, or is it normal to be higher, am I worrying for nothing. 

My  system is pure freedom 2400. 

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doug atkinson
6 minutes ago, Jango said:

Ok . So why would my tds be higher than my tap tds after the two pre-filters, that's what's puzzling me, could you explain it to me, or is it normal to be higher, am I worrying for nothing. 

My  system is pure freedom 2400. 

Where did you get the filters from?

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Jango

I got them from airforce in Leeds they are pentair?

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doug atkinson

You may find they are spent and therefore may be doing a reversal, just a thought.

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Jango

I need to email you Doug. I need some advice then. Many thanks. Is there a better make. The membrane is a axeon 1 year old. Bought the system second hand. 

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Part Timer

The fact the TDS is 286 from a previous reading of 282 means nothing, you could take 10 readings one after another from your tap and they would all be different. Your R/O membrane is still removing 96% of the solids so is still working ok. What size resin bottle do you use, and when was the resin last changed.

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Jango

The reading of 286 was after the pre-filters. The resin bottle is 6.5 litre. Changed about 3 months ago. Will double check.

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Part Timer
6 minutes ago, Jango said:

The reading of 286 was after the pre-filters. The resin bottle is 6.5 litre. Changed about 3 months ago. Will double check.

Yes but when you test your water the TDS would vary every time you measured it so you are only getting a reading of a small amount at that moment in time. The next litre that passes through could be higher, therefore I doubt your prefilters are adding to the TDS of your water.

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Jango
23 minutes ago, Part Timer said:

Yes but when you test your water the TDS would vary every time you measured it so you are only getting a reading of a small amount at that moment in time. The next litre that passes through could be higher, therefore I doubt your prefilters are adding to the TDS of your water.

Ok thank you. Do you think my resin vessel should be bigger? I read somewhere they recommend a 11 litre? 

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Nudel

The difference is probably within the error margin of your meter as well,it's negligible. 

 

Do a test with at least 10 litres, it'll average out better.

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Part Timer
36 minutes ago, Jango said:

Ok thank you. Do you think my resin vessel should be bigger? I read somewhere they recommend a 11 litre? 

I would say yes as mine's the same size and the TDS stays at zero for a few weeks, it stays at two for a few months so I've put it down to water going through vessel to quickly. I don't have a problem at cleaning with a TDS up to 5 though.

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ks789

Yes the pre filters probably need replacing at least, If you do about 2000 litres a week and changed them couple of months ago. A lot of the pre filters reccomend10 or 12 thousand litres and then replace. Remember to add on the litres of waste water too. You could see the state of the sediment filter, unscrew it out and take a look, mine was dirty after 10.000 odd litres.

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Jango
25 minutes ago, Part Timer said:

I would say yes as mine's the same size and the TDS stays at zero for a few weeks, it stays at two for a few months so I've put it down to water going through vessel to quickly. I don't have a problem at cleaning with a TDS up to 5 though.

That is exactly what is happening, mines been at 2 for about 6 weeks. I never thought about the size of the vessel, but I have been googling quite a bit, but I can’t remember where it said about using a bigger one. 

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Jango
27 minutes ago, ks789 said:

Yes the pre filters probably need replacing at least, If you do about 2000 litres a week and changed them couple of months ago. A lot of the pre filters reccomend10 or 12 thousand litres and then replace. Remember to add on the litres of waste water too. You could see the state of the sediment filter, unscrew it out and take a look, mine was dirty after 10.000 odd litres.

Ok thanks. I have a set in the garage ready, I will swap them. I need to get stocked up. I need to speak to Mr Daqua😄

 

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Iron Giant

Thought I would jump in on this about pre-filters, @spruce What's the production life of a eco-soft sediment filter, doesn't say anything on the packaging 🤔

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spruce
32 minutes ago, Iron Giant said:

Thought I would jump in on this about pre-filters, @spruce What's the production life of a eco-soft sediment filter, doesn't say anything on the packaging 🤔

 

That would depend on the sediment content of your water. Theoretically, a sediment filter could last for years if there was no sediment in the water. The reason a carbon block filter has a service life is that it can only absorb and finite amount of chlorine. Most change their sediment filter when they change their carbon filter. For us in our area we do have heavy sediment issues in our water from time to time. Something was definitely going on a couple of years ago as I was replacing a sediment filter every month and the carbon block on schedule at every 3 months based on the water we were using then.

 

The only way I tell if the sediment filter is prematurely blocking up from sediment is comparing the water pressure gauges I have on each side of the prefilters. Our WP is 50psi and when the gauge after the prefilters drops to 40psi I change the sediment filter. If the carbon block is just about ready to change then I will do both as reset the water meter. I have clear prefilter bowls and within a few hours of producing water after a prefilter change I can already start to see the sediment filter changing colour.

 

Many years ago one of the local lads phoned me up to ask for help as his RoMan type r/o wasn't producing water any longer even with a booster pump. When I open the sediment filter housing it was chocker with sediment. He told me he had changed his filters several months before. Replacing filters solved the problem.

 

 

Edited by spruce

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spruce
12 hours ago, Part Timer said:

The fact the TDS is 286 from a previous reading of 282 means nothing, you could take 10 readings one after another from your tap and they would all be different. Your R/O membrane is still removing 96% of the solids so is still working ok. What size resin bottle do you use, and when was the resin last changed.

 

Agree 100%. One of the early wfp suppliers advised me that in his opinion the cut off point for membrane replacement was 94%. So @Jango's membranes are closing in on that figure. The higher the rejection rate from the membranes the more resin one will use the polish the water off. But I would personally make the change earlier if my in coming tap water tds was high. My reasoning would be that I'm going to have to replace membranes just now anyway, so do it now and save the extra resin costs. Its all about 'economies of scale.' Is @Jango still better off financially saving money on not replacing membranes and spending a little extra on resin. Effort must also be included as part of the 'economies of scale' decision.

 

Edited by spruce

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Jango

So Spruce, you think the membrane is on its way out then. It's only 18 months I was told, when I bought the second hand system. So you think everything needs replacing. What about di to bigger vessel from 6.5 litre? Many thanks

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Iron Giant
 
That would depend on the sediment content of your water. Theoretically, a sediment filter could last for years if there was no sediment in the water. The reason a carbon block filter has a service life is that it can only absorb and finite amount of chlorine. Most change their sediment filter when they change their carbon filter. For us in our area we do have heavy sediment issues in our water from time to time. Something was definitely going on a couple of years ago as I was replacing a sediment filter every month and the carbon block on schedule at every 3 months based on the water we were using then.
 
The only way I tell if the sediment filter is prematurely blocking up from sediment is comparing the water pressure gauges I have on each side of the prefilters. Our WP is 50psi and when the gauge after the prefilters drops to 40psi I change the sediment filter. If the carbon block is just about ready to change then I will do both as reset the water meter. I have clear prefilter bowls and within a few hours of producing water after a prefilter change I can already start to see the sediment filter changing colour.
 
Many years ago one of the local lads phoned me up to ask for help as his RoMan type r/o wasn't producing water any longer even with a booster pump. When I open the sediment filter housing it was chocker with sediment. He told me he had changed his filters several months before. Replacing filters solved the problem.
 
 
Don't have an issue with sediment at all, I just have one as a precaution

County Durham Lad

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Iron Giant
So Spruce, you think the membrane is on its way out then. It's only 18 months I was told, when I bought the second hand system. So you think everything needs replacing. What about di to bigger vessel from 6.5 litre? Many thanks
It might only be 18 months old but it's about how much water it has processed within that time frame the other guy could have had it running 24hrs a day 7 days a week.

County Durham Lad

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Jango
1 hour ago, Iron Giant said:

It might only be 18 months old but it's about how much water it has processed within that time frame the other guy could have had it running 24hrs a day 7 days a week.

County Durham Lad
 

He only worked part time, it wasn't producing everyday, only did 3 part days. But I guess it's one of those things. 

I have checked back and my pre-filters went in on the 15th June, so they will need changing.

how long do I need to flush them for, is it around an hour or so? 

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ks789

I reckon the membrane can deteriorate if not in use for too long or left dry, not too sure on this though. If its had all un-pure tap water in it, then been left a while you'd think this could be a cause of trouble. All you can do is try. Yep, flush through all to waste after membrane and see.

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spruce
6 hours ago, Jango said:

So Spruce, you think the membrane is on its way out then. It's only 18 months I was told, when I bought the second hand system. So you think everything needs replacing. What about di to bigger vessel from 6.5 litre? Many thanks

 

I bought a second hand system when I first started wfp and that was a year old. The membranes were also on their way out (which I didn't know) as the original owner never replaced prefilters in the time he owned it. He did it for me but it was too late by then. I learnt a valuable lesson. Never buy a second hand r/o and if you are tempted only pay the second hand value of the housings - be prepared to have to buy new filters and membranes and take that into consideration when determining a price. In most cases the result will be to buy a new one to begin with.

 

Sellers will say anything to make you happy about the price they are asking. You know the drill; "this is a one owner car lovingly looked after by a careful old lady."

 

I have a 6.5 liter di vessel and its fine for me. My pure after r/o is 2 to 3ppm so a I only replace resin once a year on average. The bigger the di vessel the longer the time between resin changes, but it also means its heavier and bulkier when trying to empty the resin from the di vessel when you do have to change it.

Edited by spruce

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Jango

Many thanks to everyone for helping me out. 

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