What's new
  • Please note members who been with us for more than 10 years have been upgraded to "Veteran" status and will receive exclusive benefits. If you wish to find out more about this or support IcMag and get same benefits, check this thread here.
  • Important notice: ICMag's T.O.U. has been updated. Please review it here. For your convenience, it is also available in the main forum menu, under 'Quick Links"!

pH meter calibration

Wismo

Member
So I been having problems with my plants,
Just checked my phmeter and in a 7.0 solution I got 7.6 I think it's cause me problems.

How often do you have calibrate...
 

AgentPothead

Just this guy, ya know?
I think the rule of thumb is once a year at worst, every 6 months normally. If it's a halfway decent ph meter it should have a calibration screw on it you can get a tiny screwdriver and fix it.
 

Cvh

Well-known member
Supermod
My bluelab PH meter gives an indication every month to calibrate it.
 

Capt.Ahab

Feeding the ducks with a bun.
Veteran
Yup. Every 30 days at the very least for a quality meter like a Bluelab.
I calibrate mine every two weeks.
Cheaper meters I would do at least once a week or better yet, get a better meter..
 

Wismo

Member
Yup. Every 30 days at the very least for a quality meter like a Bluelab.
I calibrate mine every two weeks.
Cheaper meters I would do at least once a week or better yet, get a better meter..

I'm on the cheaper side got my 7 and 4 solution now it once a week. I don't trust it too many problems I'll probably invest in a blue lab
what do you guys recommend
 

Cvh

Well-known member
Supermod
I'm on the cheaper side got my 7 and 4 solution now it once a week. I don't trust it too many problems I'll probably invest in a blue lab
what do you guys recommend

Indeed invest in a Bluelab PH meter. For small scale grow you'll be fine with a Bluelab PH pen meter. For bigger grows you would want maybe one from the Bluelab professional lines with an external probe.

Bluelab PH pen meter are in my experience one of the best meters out there.

Also get yourself quality calibration liquids. And throw it away after use. Don't add it back into the bottle.

I use this one.

bluelab-ph-pen.jpg
 

Cvh

Well-known member
Supermod
Here is a short video on how to calibrate a Bluelab PH pen meter.
https://www.youtube.com/watch?v=EYL62M9Y9CQ

Just a remark about the video.
It's best to keep the probe into a shotglass submerged into the kcl storage liquid instead off adding a few drops in the cap. I find that with just a few drops in the cap the probe isn't sufficiently protected.
Don't even for a single day let the probe dry out. It needs to be kept wet into the kcl storage liquid.
 
Last edited:

GOT_BUD?

Weed is a gateway to gardening
ICMag Donor
Veteran
Here is a short video on how to calibrate a Bluelab PH pen meter.
https://www.youtube.com/watch?v=EYL62M9Y9CQ

Just a remark about the video.
It's best to keep the probe into a shotglass submerged into the kcl storage liquid instead off adding a few drops in the cap. I find that with just a few drops in the cap the probe isn't sufficiently protected.
Don't even for a single day let the probe dry out. It needs to be kept wet into the kcl storage liquid.

Listen to this advice. My bluelab drifts all over the place now because I didn't keep the probe wet.

My $15 one that I replaced it with has been rock solid though.
 

Cvh

Well-known member
Supermod
It's best to store a pH meter in 4M KCl storage solution.
(Some pens require a 3M solution instead of a 4M KCl solution, check with the manufacturer)

Here is some info I found why this is needed:
The presence of concentrated KCl solution keeps the ionic conductivity of the glass membrane in good condition. The conductivities of K+ and Cl- ions are the same.
KCl is not a buffer solution, and is never used to calibrate the pH electrode, but is used to keep it working properly - it keeps the glass full of ions.

Just to give you an idea, when I was still growing synthetically I spent around 20 € annually on calibration liquids and KCl storage solution.

I grow organic now. There is no need to pH/ec when you grow organically.
 
Last edited:
Top