Somewhatshocked, are you talking about the light blue opaque plastic one or the darker blue with more translucent plastic. There is a few different "blue" models on Ebay, and most don't have a brand name with them. Thanks for the clarification, as I may be purchasing one soon.
do you still need to callibrate a TDS meter then? when you buy them do they come callibrated?
i do have a ph pen the cheap yellow ones on ebay but i never seemed to have much luck using it on my old shrimp tank as it never stayed stable it kept rising as the water moved round? i did callibrate it but in the end gave up
do you need to store them in a liquid as i also read that if you dont store them in a liquid then they stop working anyway?
im about to buy an R/O machine and guess a TDS meter would be needed really but not checked as i have been buying my RO in
I use this one as well. Just got it a couple weeks ago, actually. I didn't get any calibration solution, but then again, I work in a Chemistry research lab, so I have access to Milli-Q water as well as stuff to make my own calibration solutions.
They come calibrated from the factory, but I never trust them. I read somewhere on this forum that a member's meter from the factory was over 50ppm off out of the box. If you are planning on being in the lower TDS range, you don't really need to get the 1000ppm calibration solution.