Bluelabs Conductivity pen question

[Littylovesdapiff]

I just bought a bluelab Conductivity pen, which i have in the picture below. It was an attractive price to replace my untrustworthy cheap yellow tds meter and from what I see it measures ec ppm 500 and ppm 700. When i recieved it, i was under the impression it was already calibrated and tested my tap water which i know is a little hard. It read 0 in all scales. I have ec calibration solution coming tomorrow but i was just wondering if anybody had experience with this pen at all. I looked at other models which i think are older and seen them labeled as PPM pen and not Conductivity pens. Also which scale do i use for tds? 500 or 700?

 

[Mañ'O'Green]

I just bought a bluelab Conductivity pen, which i have in the picture below. It was an attractive price to replace my untrustworthy cheap yellow tds meter and from what I see it measures ec ppm 500 and ppm 700. When i recieved it, i was under the impression it was already calibrated and tested my tap water which i know is a little hard. It read 0 in all scales. I have ec calibration solution coming tomorrow but i was just wondering if anybody had experience with this pen at all. I looked at other models which i think are older and seen them labeled as PPM pen and not Conductivity pens. Also which scale do i use for tds? 500 or 700? View attachment 1325376

You can use any scale you want. The world uses EC except for the USA we use the Hanna 500 PPM scale.

I have a different brand Horiba COND (EC) meter. It must be calibrated every time you use it.

 

[Delps8]

I use that EC meter and the matching pH meter as well as the Bluelab EC and pH monitor. They are quality products.

For my grow of 4 gorilla grow autos, I have had to switch to PPM instead of EC because EC wasn't sufficiently granular. The 500 PPM readout was the only way to be able to change the TDS in my res to get just the right level. With that level of granularity, I've been able to change a res that was 500 PPM (EC of 1.0) and dilute the nute level in steps of 490, 480, 470, etc. Those are tiny changes but, using the 500 PPM scale, I could make those changes. If I were using EC, the closest I could get would have been 1.0, 0.9, 0.8 (500, 450, and 400 PPM) and those changes completely missed the sweet spot for TDS.

BTW, all TDS meters measure EC and display that as either the EC value or they convert it ti the 500 PPM scale or the 700 PPM scale (in Australia and NZ I think).