TDS Meter Calibration

mark · #1 10-23-2009, 11:26 PM

I'd be interested in the low end accuracy. 220 or 290 not a lot of difference in the big picture, now is 001 really 001 or 010

mike31154 · #2 10-24-2009, 01:58 AM

Once my system is running for a few minutes, the RO output TDS is 001 and the DI output is 000. On initial start up the RO reads about 114 or so. I guess I should test the handheld with some 000 DI water out of my system.

Myka · #3 10-24-2009, 03:15 AM

I would calibrate both of them using 342 ppm NaCl califbration fluid, and then re-check. I know mine is difficult to calibrate (it's a $30 handheld)...so I wonder on its accuracy.

mike31154 · #4 10-25-2009, 03:34 AM

Thanks for the advice Mindy. Where's a good source for the calibration solution?

Not sure it's even worth calibrating the handheld, I think I paid less than $20 for it. My RO/DI system is barely six months old so I'm fairly confident in the Dual TDS meter that came with it, especially since both probes on that yielded identical readings for my source water. Being relatively new, I trust the RO and DI TDS readings since the filters should be nowhere near exhausted. My DI resin has only changed colour to about one quarter of the canister height.

Besides, even if the readings are a little off at the low end, I'm not too concerned since I was using treated tap water up until six months ago.