pH pen calibration juices

[DabberDog]

I need to calibrate my Bluelab pH pen. Their calibration juices look like the most expensive on the market.
Will any juice do the trick, or do I need to stick to their product?

[Orggrwr]

Seems to me any juice would work as long as the ph is spot on. Can't think of a reason you would have to stick with same company but I could be missing something. I started growing in living soil about 2 years ago and haven't used my Apera since then. Come to think about it I'm not even sure where it is.

[OldManGrower]

PH is PH. Doesn't matter.

[DabberDog]

I ask because one brand said it worked with 'most' of the name brand instruments. That 'most' word threw me for a loop. I agree, pH is pH.

[Allenpro]

Why would they say that? I understand each pen may be a little different but once the are calibrated they should all result in the same readings. I would ask, maybe its a CYA statment
Back to your original question, I have several on hand because I forget I bought them and the Blue Labs, GH and several others give the same results

[DabberDog]

CYA. And the odd stoner who can't figure out the instructions. And China brand products. I am the sort who believes in spending money on quality and making sure there is a helluva fine return policy. Buy the best I can afford (not necessarily the most expensive) and ride it into the ground.
But I'm to a point where using the pen is superfluous to the experience of doing the same thing for so long. I haven't had to make a second adjustment after the initial pH down in years. This question arose from finding I need to add a good bit more down to get the money shot. So, I'm not using the pen until I get it calibrated and just adding what I know to be a typical dose.

[Allotrope1000]

Hi, Dabber.
I buy a new, cheap $10-$15 pH pen every two years or so. With the new pen comes foil packets of pH powder to make the calibration solutions. I use my analytical balance (+/- .001g) to weigh out just a portion and save the rest to mix for future calibrations. I only calibrate the pen to +/- .1 pH as I think +/- .01 pH is overkill for the grows.

Any degreed chemists in here who can get into the pH solution "weeds"?

I had a coco grow two years that was slow to to vegetate. Yep. Bad meter, pH off. A new meter fixed everything.

[Bluey]

The Apera Amazon shop for all things pH.

[2ShedsJackson]

I use semi skimmed milk. In the UK It's ph is 6.5 which is just about where you want it for most grows. I've never reset my pen meter yet 'cos it's never needed it.

In a similar vein, i don't use ph up/down, I use lemon juice when needed.

[Timmeeeh]

Can you explain this further? I'm curious how semi-skimmed milk keeps you from having to reset your meter.

[2ShedsJackson]

I check my ph meter regularly with semi skimmed milk. If it reads 6.5 +/- 0.1 then I know it's good. So far it's always been within those limits so no further action needed. If it started to drift a bit I'd just factor that into whatever reading I get when checking my feed water.

[Allenpro]

OK, sorry to be the naysayer, but how do you verify the Milk PH is 6.5?

[Ckbrew]

Calibration solutions are buffer solutions. They hold a specific pH based on their chemical composition. If something is added that might change pH the solution will correct itself. This only lasts until the buffers are used up, then the pH will change. So long as the buffer or calibration solution(s) matches the meter's pH calibration point(s) it should work. Many meters calibrate at multiple pH readings for more accurate results. remember pH is a logarithmic scale. The difference between 7 and 6 is not a factor of one, it is a factor of ten.

[golfnrl]

I use a BlueLab PH pen. I've used GH calibration solution with it no problem. I am currently using the BlueLab product but only cause the grow shop was out of the GH when I was there.