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Puzzled by tds reading.

Jango

Well-known member
Messages
833
Location
West Yorkshire
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? 

 
Have to calibrated you tds meter recently?

higher TDS after carbon filter could be a dodgy cartridge.

what gpd is your membrane?

 
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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?

 
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. 

 
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?

 
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. 

 
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.

 
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.

 
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? 

 
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.

 
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.

 
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.

 
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. 

 
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?

 
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 ?

 
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.

 
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