TDS question

[Jbissell1289]

So I just got an upgraded DI unit from BRS that includes an in-line TDS monitor.

My question is this: TDS coming out of the RO filter is 108-113, this seems pretty high, is that normal?

TDS coming out of the full system is 0, but I'm just not sure if my RO filter media and membrane is bad or not.

Thanks!

 

[Chris.Reef]

TDS coming out of the membrane should definitely not be that high, 4-6 at the most depending on what your source water is like. With it being that high it is depleting your DI resin rapidly. I would remove the RO cartridge and inspect the o-rings and make sure it is installed properly.

 

[Jbissell1289]

Ok, that is what I was thinking. Do RO resins deteriorate over time? It wasn't used, but it was probably about 10 years old and just sitting.

 

[Chris.Reef]

If they didn’t get wet and was stored properly then I think you should be fine.

 

[Reefer508]

My guess is the RO membrane is dried out. Worth just replacing it.

 

[Jbissell1289]

Well I feel like an idiot… found the reason. The guy I got it from a while back said it was new and that he had an extra ro membrane for it.. I guess I should have checked for myself! I had a brand new one in a sealed package. So here are my numbers with the membrane installed! Never trust what people tell you. Just check for yourself I guess.

 

[Jbissell1289]

This explains why my sps is not doing well at all.

 

[afboundguy]

That makes much more sense... TDS of 6 post RO membrane is much better...