When to change the resin of DI vessel n1 ?

Hello,

I’m filling my WFP system with rain water only which is between 40 and 45 PPM.

I use 2 DI vessels in series.

I would like to know at which PPM level of the DI vessel n1 I should consider it’s time to change the resin of this DI vessel.

I personally was thinking that the good moment is when the DI vessel n2 begins not be at 0 PPM anymore.

What’s your point of view ?

My point of view is you are correct! 

Gilles Millecam said:

Hello,

I’m filling my WFP system with rain water only which is between 40 and 45 PPM.

I use 2 DI vessels in series.

I would like to know at which PPM level of the DI vessel n1 I should consider it’s time to change the resin of this DI vessel.

I personally was thinking that the good moment is when the DI vessel n2 begins not be at 0 PPM anymore.

What’s your point of view ?

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That sure is filthy rain. Its about 15 or so here. Maybe clean the roof? or could be the clouds came through industrial area or something.

Depends what your happy to clean with. As soon as second vessel goes up beyond that then its time. Mine is currently at 5 and I've got no problem in cleaning with that still. 

I never even check what it's coming out the first vessel at. 

I use two DI vessels - the only TDS I keep an eye on is what comes out my wfp. When that gets north of 15 I usually do a resin change. I switch the two vessels around ( only replace the resin in the vessel that was previously first in the chain). This maximises resin efficiency. 

I know a good windy who runs his tds up towards 25-30 and just rinses more thoroughly when his TDS gets high. Havent tried it myself though I prefer the low numbers and peace of mind.

why do you use 2 DI vessels?theres no need until your tds starts to rise.....only then put another vessel in tandem to get the most out of your resin....

dazmond said:

why do you use 2 DI vessels?theres no need until your tds starts to rise.....only then put another vessel in tandem to get the most out of your resin....

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I think he is already using 2 now tho. 

The higher the TDS when you change it in a double DI system the less time it will last before it is showing above 0ppm again.