ro/di tds

It depends on what you tap water and RO only TDS readings are. You cannot say good or bad without knowing all the information. Personally I change DI cartridges at anything over 1.
 
FyI, my tap water in Sarasota reads around 188 ppm and after going thru my RO/DI I get 0 ppm. I think the 188 is considered relatively good water as I have seen some people state theirs is much higher.
 
<a href=showthread.php?s=&postid=10109169#post10109169 target=_blank>Originally posted</a> by george1098
how long has it been since youhave changed the cartridges in your RO/DI unit? what kind is it?

My Aqua FX Barracuda has gone almost 5 months since I change any of the filters but the weather has been cooler until now. I checked it last week thinking I would need to change them, but the Hanna TDS meter read zero. My system is in my garage and since it is hot here in the summer I usually will not be able to go more then several months before swapping filters.
 
Prefilters and carbons should always be changed every 6 months at the longest. This is for a couple of reasons, one is to ensure you have sufficient pressure available to the membrane, another is to help reduce the possibility of viral or bacterial growth inside the housings. This is especially important if you use the unit for drinking water and if it is exposed to direct lighting an temperature extremes.
Prefilters and carbons have very little to no effect at all on final TDS readings, thats the job of the membrane and the DI filter. The prefilter and carbon are there to protect the membrane for the most part.
 
I get my RO from a crappy Sears tap water RO filter, 2 carbons and 1 RO membrane. It constantly produces 20 TDS. My tank has been fine, but I've got a bit of a phosphate problem, but I've tested straight tap water for phosphate and there is none, so it's gotta be from food.
 
i replaced everything about a month ago..the water comes from a well and goes through a whole house filter and water softener before it hits the ro/di unit which is a purely h2o optima automated edition.
 
Out of curiosity what is your incoming TDS from your well?

I suggest checking your TDS at three points:
Incoming
After the RO (measure after the system has been running at least five minutes!)
After the DI

The TDS after the RO membrane should be significantly less than 1-3% of the incoming TDS (97-99% rejection rate). If it isn't then you need to look at your RO membrance operation (including incoming pressure).

4 ppm after the DI isn't all that much but you should be able to reduce it to zero. A second DI add-on would easily do the trick.
 
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