TDS is 16ppm. Is that alright for my tank?

[arminkropp]

Wondering if a TDS reading of 16-18ppm is alright. My tap water is absolutely horrid at 560-580ppm so I'm getting about 97% rejection. My DI resin cartridge is still half blue. Tomorrow I'll see what my reading is before DI and see if its my membrane causing my problems.

If I cant see anything wrong, is 16ppm safe to use?

TIA

 

[arminkropp]

I just checked my TDS after the membrane but BEFORE the DI. Getting a reading of 36ppm. That works out to a 94-95% rejection considering it going in at 560-580

Now looking at my DI closer, I'd say its close to 80-85% exhausted. I know I'll need to replace it, but am I depleting my DI resin prematurely with my TDS at 36ppm going in to it?

Whats normal. Or is this just "My" normal seeing my feed water is so poor.