tds

[tigershark4]

what should the tds read on a tds monitor? when should you change the DI chamber?

[smleee]

TDS should be 0ppm after the DI. To know what to replace you need to know your input TDS, RO TDS, and DI TDS. Prefilters should be replaced every 6 months regardless; usually the DI is next to go, then membrane (all depending on usage and input TDS).

eee

[tigershark4]

My tds is reeding 29 to 31 before the Ro and then it is reading 19-21 after the DI. I then changed the DI and it went down to 14. I changed the carbon and prefilter in the middle of February. Any thought

[smleee]

So:

30 ppm before the RO

? ppm after the RO (and before DI)

20 ppm after DI


If you are getting 30ppm before the RO, depending on what membrane you have, you should be getting somewhere between 3ppm and 1ppm after the RO (90-98% rejection ratio depending on the membrane). Then after the DI (new DI) you should get 0ppm. Please let us know the ppm after the RO and before DI. Also, do you have any kind of post carbon filter after the DI?

eee