Mindy, have you some more info on this ?
I'd like to know if I'm looking forward to some kind of failure :surprise:
I currently own the DM-1 and the SM-1

What info do you want? Google for owner's manual for the DM2 to compare. Have you tried calibrating yours yet? Put both probes into the same glass of tap water and see if they read the same. If they do you're lucky (for now), if they don't read the same then there is nothing you can do to get them to read the same. Then you need to set the lower reading one to the calibration solution (usually 342 ppm), and if the second one then reads 3 ppm higher you just have to remember that 3 ppm on the second one means "0". That's about all you can do.

I wasn't expecting to hear issues

I've never had to cal mine since I bought them
Looks like I'll have some fun to deal with in the near future ...

Oh, and thanks for the info :smile:

Thanks again Mindy for the info
Every day there is something to learn about
Sucks that it's about my own gear :wink:

I have a dual TDS meter, one shows after RO and before DI, and the other shows after DI. When the RO tds starts to go up, it tells me it is time to flush the membrane. My final RO/DI water is normally 0 or 1. When it goes up it is time to change DI. When flow slows down, it is time to change the sediment and carbon filters.

Pretty much what I was trying to say about TDS meter locations

Do you have a pressure gauge ?

What do you mean you've never had to? How long have you had the meter? You should calibrate every 3-6 months.

I have a pressure gauge on the input source side only, which is my house pressure, and it is normally around 70.

I calibrated them when I set the unit up in May, so I guess I'm due for another cal session
I thought they were good for a year :rolleyes:

My input pressure is around 60psi
My pre-RO pressure (post sediment and carbon filter) is the same, but when it dropped below 50 this last fall, I replaced my sediment filter and all was good again