necessary to recalibrate TDS meter?

[CNGH]

i changed the batteries on my HM tds meter (pen/dip style, not inline) a few months ago...do i need to recalibrate it?

i actually have 2 tds meters, the HM i've had for probably 7 or 8 years, and a freebie from air/water/ice i've had a couple years (i also replaced its battery after it died early last year sometime). both read 0 tds when i test my ro/di, but have different readings when i test my tap water. the HM is 180ish, the one from awi reads 230ish...

any help/ideas appreciated. thanks!

 

[five.five-six]

I don’t think you can recalibrate a TDS meter at home. Somewhere I ead about it and it seems to be accurate, it needs to be done with liquid flowing past the sensor

 

[Boochika]

i changed the batteries on my HM tds meter (pen/dip style, not inline) a few months ago...do i need to recalibrate it?

i actually have 2 tds meters, the HM i've had for probably 7 or 8 years, and a freebie from air/water/ice i've had a couple years (i also replaced its battery after it died early last year sometime). both read 0 tds when i test my ro/di, but have different readings when i test my tap water. the HM is 180ish, the one from awi reads 230ish...

any help/ideas appreciated. thanks!

There are some documents online for HM TDS meter calibration you can find through a google search.

From what I've read after looking at this subject myself, I think each has it's own 'range' of calibration, so each should be accurate to 0 TDS, but the high and low ranges of each could vary. If I had 2 I would try to calibrate 1 and see how it turns out.