Calibration

[monstermash]

As a hydro grower I need to be sure my PH and EC meter is working correctly. I calibrate often. What does Pulse recommend on the subject of calibration? I imagine there are reason and way for the sensors to be out of calibration. Does Pulse have any guidance on the subject? Do you offer that as a service or refer to a calibration lab for that? I am specifically referring to temperature and humidity as I have the one, not the pro (yet).

My guess is lab time for such a calibration is likely cost prohibitive, but while I trust Pulse I would love to be able to validate the data.

[OC_Grower]

You can assign the calibration values to the PulseOne on the Settings page.

Re. determining those values - for temperature, I calibrated a ThermaPen InstaRead to 32 and 212, left it at room temperature, and then checked the Pulse against it. I don’t remember what the variance was, if any.

For RH, Google “calibrate RH using salt” and you’ll get a lot of hits that lead to essentially the same process. I calibrated an AcuRite hydrometer to 75% and then checked the PulseOne against that.

I’ve used 5 sensors from 3 companies since I got the Pulse and I rely on the Pulse.

[peet]

The sensors are very time-stable and come pre-calibrated to a high degree. If you place your sensor correctly in your grow (minimize direct light to prevent heating, at canopy level, with good airflow), then you can be confident in accurate results.

We don’t offer a calibration service, beyond our original calibration from manufacturing. I would agree with you that lab time for a calibration isn’t worth it.

[Noah]

All my temp and RH sensors from every manufacturer are very stable and seem to be ok for years, however here’s an important tip: I suggest you cover all sensors or remove them from the grow during times when spray may hit the device.

CO2 on the other hand, every meter in my building reads different and my Pulse Pro is at one end of that spectrum. The only time my CO2 sensors come close to matching each other is when I bring them outside. How do I know which sensor is correct? I don’t. How could I? No practical way. Calibrating to outside doesn’t seem to work because it’s so far from what we use in our grows in both temp, humidity, and CO2. In this case I just go with the average of everything I use and if something seems way different I discard it

[peet]

Calibrating outside during the daytime is probably your best bet. Don’t do it at night because CO2 levels increase at night due to plant respiration.

[Noah]

The problem with most devices is that they assume 400 is ambient. That hasn’t been the case for a long time, and especially not in the middle of Los Angeles during the middle of the day when all the cars are respirating

Another issue that I face is that the further the room is from the calibration point, the less accurate it is. So if you calibrate ten devices (especially from different manufacturers) all to “400” outside, then bring them into a room with 1500ppm CO2, 15 degrees warmer and 40% more humidity, then they are (in my experience) not going to agree. You just have to say “this meter is that meter plus 200” etc.

Some meters allow you to set the current CO2 level as a calibration and IMO that’s much better. At least that way you can set ambient to 419 for the next 6 months and whatever god awful level it’ll be at next year.

What would be really nice is if I could calibrate all my devices to the same reading at my room’s setpoint. I want all my sensors to agree at 1500 not 420.

[peet]

You can type in a custom value to calibrate it to, so just type in 420 when doing your outdoor daytime calibration.