Jestersix

RODI Replacement Cannisters

I test Tds main input, at output of of carbon blocks(input of ro membrane) at input of di and at output of di.
My main input is aweful around 135,
My ro membrane output.is around 12 and my di output is 0

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135 isn’t so bad imo, I had 660 when I lived in Santa Barbara. It’s whats in the ppm more so than the number anyway.
Seems like you should be getting lower ppm out of the membrane. Only reducing 90% seems a little low. I though it was supposed to be closer to 98%. Obviously depends what’s in the tds and temperature and pressure you push it through at as well tho.
 
I test Tds main input, at output of of carbon blocks(input of ro membrane) at input of di and at output of di.
My main input is aweful around 135,
My ro membrane output.is around 12 and my di output is 0

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Same here for testing locations, but what is your output after carbon blocks? Mine is higher after carbon than straight from the tap.
 
135 isn’t so bad imo, I had 660 when I lived in Santa Barbara. It’s whats in the ppm more so than the number anyway.
Seems like you should be getting lower ppm out of the membrane. Only reducing 90% seems a little low. I though it was supposed to be closer to 98%. Obviously depends what’s in the tds and temperature and pressure you push it through at as well tho.
Yup my membrane need changing. It's so so so old am just milking it ha ha

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It’s probably more economical to change it rather then go through di resin faster which you are doing this way.
I bet it is.
The honest truth is that opening the membrane canister was such a pain I am so lazy to go over it again and will prob just buy full canister and filter together ha ha

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Apologies, I meant to say, she was saying her system have the same location for the tds meters that I have. To which you replyed something is wrong. So I said she is not talking about tds reading.

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No, I replied it doesn’t seem right that tds would go up after her prefilters. Nothing to do with you at all.
 
No, I replied it doesn’t seem right that tds would go up after her prefilters. Nothing to do with you at all.
Oh oh, then i missunderstood.
But why you think it's wrong? You can have as much tds meters as you like and any stage you like..what's the harm?

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Oh oh, then i missunderstood.
But why you think it's wrong? You can have as much tds meters as you like and any stage you like..what's the harm?

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Misunderstanding again. I’m taliking about tds increasing after prefilters. Nothing about meters.
 
My sediment and 2 carbons were less than two months old but I changed them because tap TDS was less than post-carbon. Unfortunately, I always mean to keep track of the volume of water processed but never do. Now, tap is 170 and post-carbon is 200. I was careful to rinse the carbon a lot, too.
Water filtration is always messing with me! Added a second DI canister as I think @Coral reefer suggested to pair old one with a new one. Got a second RO membrane to add to my getting-old membrane but haven't hooked it up yet. I think I go thru all my media too quickly. YEP = I need to measure how much water I process. I will consider the meters I have seen discussed in the forum so it actually gets done.
 
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The only way I can possibly think why your TDS is higher after is simply due to how the TDS is being read.

My first thought is swap the probes from before and after prefilters, make sure both are aligned in the same fashion with respect to the water they're going through.

My second thought is because TDS meters work on measuring conductivity perhaps when the water is "dirtier" it doesn't conduct as much, giving you an false positive... and a little googling shows this
"Since, activated carbon does not remove most inorganic compounds from water; TDS is not an effective way of measuring the product performance. In fact, carbon adds some inorganic compounds to the water. As water passes by carbon, trace amounts of some inorganic compounds dissolve in the water. These compounds can be potassium bicarbonate, sodium bicarbonate, calcium carbonate and carbon dioxide. Therefore, activated carbon can increase a measurement of the TDS. This effect is more pronounced with a new filter. As a filter is used this effect decreases because these inorganic materials are flushed out of the carbon. "
 
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