RODI Filters

[JonnyTorch]

Hey all. After a long while I decided to use my own RODI system and mix my own salt so I don't have to go to the LFS every week.

My RODI is pretty new, (I've had it for a couple years, but never used it) and a TDS meter reading out as 0.

I've googled this, and can't seem to find a precise answer anywhere..

If I have a TDS meter and my RODI starts to say 1, 2 or 3 with the TDS meter, how do I know if I need to change out individual filters, just the DI resin, just the membrane or all? How to know what component is making the numbers rise?

Thanks! (This is preemptive - I just want to know for when it does rise.)

 

[208reef]

These are the instructions given with SpectraPure RO/DI systems. Might be different for other manufacturers.

Micron filter - Change every 4-6 months or once you see a 15% PSI drop from normal on the pressure gauge
Carbon filter - Change every 4-6 months or once you detect 0.1ppm total chlorine from the product water using a test kit (total chlorine, not free chlorine)
DI resin - Change once TDS >1

They don't offer any info in their manual about how often to change the RO membrane and someone may have a more scientifically accurate answer, but if I am remembering correctly I believe most people replace them every 1-2 years.

 

[JonnyTorch]

These are the instructions given with SpectraPure RO/DI systems. Might be different for other manufacturers.

Micron filter - Change every 4-6 months or once you see a 15% PSI drop from normal on the pressure gauge
Carbon filter - Change every 4-6 months or once you detect 0.1ppm total chlorine from the product water using a test kit (total chlorine, not free chlorine)
DI resin - Change once TDS >1

They don't offer any info in their manual about how often to change the RO membrane and someone may have a more scientifically accurate answer, but if I am remembering correctly I believe most people replace them every 1-2 years.

Alright. thank you. that's pretty precise. I appreciate it. Mine is the BRS 4 stage, like the image pictured, so no pressure gauges visible. I'll have to figure it out.. Mine has been sitting on the shelf for 2 years unused, I've maybe used 20 gallons out of it total so far, but hooked it up and it's still saying 0 TDS, so I'm good for NOW. If I continue to use this regularly I imagine next year get a membrane and when the TDS gets above 1 I can just change the carbon and the DI resin together. Idk, still figuring it out! This was actually a gift to me. Thank you.

 

[KStatefan]

To determine the condition of the membrane monitor the rejection rate of the membrane. To do this you need to know the TDS of the water before and after the membrane.

 

[Buckeye Hydro Verified Sponsor]

You'll want to add a pressure gauge add on kit - without it (and a TDS meter) you are flying blind.
https://www.buckeyehydro.com/pressure-gauges-1/
When it does come time for a filter change, you may want to upgrade to a 1 micron sediment filter and a 0.5 mic carbon block
https://www.buckeyehydro.com/premium-ro-filter-kit/