RO/DI filter change

[EZMAC114]

What filter do you change on your RO/DI unit when the TDS is getting higher? And is 4ppm too high to use? I changed the resin filter because the color changed but the TDS didn't go lower so I'm thinking I might need to change the DI filter.

 

[mike007]

The di filter change should help.

 

[azjohnny]

It would be a good idea to get a hand held TDS monitor, this way you cant the water quality had the different points to properly troubleshoot. From what you have said It sounds like the DI needs to be replace ( which is resin)

I have a Spectrapure Maxcap which has 2 DI cartridges

I change out the sediment and carbon filters once a year ( they serve to protect the membrane from larger particles) and when I get 1 ppm after the first DI I change it out, it will last 3 cartridge changeouts than I will change out the 2nd

 

[AZDesertRat]

You need 3 TDS readings to troubleshoot a RO/DI system, Tap water, RO only and final RO/DI.
A good handheld TDS meter is your best friend an about $25.
You replace the sediment and carbon block filters every 6 months like clockwork regardless of usage, TDS or gallons produced. Their sole purpose is to protect the RO membrane so have very little to absolutely nothing to do with TDS, they remove big particles, suspended solids not dissolved solids(TDS) and chlorine.
The RO membrane does 90-98% of the TDS removal so monitoring the TDS at that point is critical, if it starts to fail then the DI must do the bulk of the work and it is not designed to do so. The DI removes the remaining 2-10% and anything other than 0 TDS is not what you want to use in your reef.