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how often should I change my RO/DI filters?


ssappington

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If it's been a year change them all. What TDS meter you using? I have a triple inline one that makes it easy to tell what needs changed. I read incoming to unit, after membrane, and output. This way if see your after membrane number rising you likely need new pre filters, if that doesn't fix it, time for a new membrane. Also with output you know if your DI is exhausted when compared to the membrane out. The triple meter is probably the best $35 I've spent on my RO system. Highly recommend one.

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I haven't changed mine in 4 years and my TDS is still 0.

 

It depends a lot on where you live and how much water you are using. My last house the TDS out fo the tap was around 8, so the RODI filter had very little to filter. At my current place the TDS is about 20 last time I checked. In contrat in California I would have to change them every 6 months or so but the tds out of the tap was something like 600 if I remember right.

 

I very rarely do water changes, sometimes years in between, so I do not use the filters that much. Right now I go through about 5g's of top off water a week and probably 300g total of water a year. So while it might be gettting time soon, for now, all is well.

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it's been over a year and probably 1500 gallons, TDS still reads 0

my prefilter looks NASTY!

should I change:

-nothing until TDS rises

-sediment prefilter

-prefilter and carbon block

-prefilter, carbon block AND DI resin

 

Interesting, my inline meter reads 2, tested with a TDS HM Digital Pen tester, it reads 16.  Have my new triple TDS inline meter (thanks BlueZ for the tip), will get a third opinion from it.  Someone is not being truthful!

 

So, yeah, I am seeing a decline as of late, hard to explain.  Perhaps this is related hard to say but if I am at 16 that probably is not good  :unsure:

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Triple Meter vs HM Digital

 

Tap in - 

Triple 148, HM 160 (both vary)

Post RO - Triple 2 (after settling)

Post DI - Triple 3, HM Digital 6

 

The triple clearly shows that RODI has to run for 30 seconds to flush.  

 

All in all they are close, the variance above was due to not flushing the system long enough.

 

TDS started out at over 16 and worked its way down after 30 seconds or so, it would be nice to get an RODI dump pump for startup, just might do that.

 

Time to change out DI!

 

 

=======================================

 

Sorry Steve if I derailed the thread!

 

I make 150-300 gallons at a time in that big tank you brought up from Oxx.  I have made probably a few thousand gallons to get the membranes / filters / di into this shape.

 

We are on a well system, water could come from any of three different wells.

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