Aquacontroller Standard vs. Lab Grade Probes

[bwanders]

Looking at the Aquacontroller II and its not clear to me what the lab grade probes get you. Are they worth the extra money?

[North Bay 101]

The lab grade probes give you a more accurate readings. I don't care if my pH is 8.10 or 8.11. The measurements are approximate anyway. I use the standard grade probes.

[wlagarde]

Both probes will provide the same accuracy and the accuracy and precision of the aquacontroller is superb (if appropriately calibrated). The difference is in the life of the probes. The lab grade probes are double junction (referring to the reference junction) probes while the standard grade probes are single junction probes. A double junction probe will last longer. Hope this helps!

[bwanders]

Thanks guys. So they last longer. Any idea how much longer? I assume these things have to be kept wet all the time anyway??

[wlagarde]

In general this is usually the difference between the 2 probes, however, after a little research it appears there is some vaiability on this. Some manufacturer's lab grade probe is only single junction. What makes this probe different from their standard probe? It is built more rugged, etc. In my opinion this is not worth the extra money since it is in general the junction issue that is most important for probe life (unless you regularly beat the probe around). Lab grade probes might last 50-100% longer, however, this is variable. If you can get a double junction probe for less than 50% more cost, go for it. Otherwise go with the standard grade probe.