Calibrating ph meter with different then factory solution

[beervoid]

Hello,

I just got my mw101 and it comes with a 4.01 and 7.01ph buffer solution.
Ive been looking around to order some more packages but the more economical option available is a 6.86ph solution.
Could I use this for my mw101 to calibrate it or should I go with the same 7.01ph that came with the device.
Thank you

 

[thehaze]

You should stick to the 4 and 7 pH solutions, as your pH meter is intended to be calibrated with those. When you calibrate it, it shouws you need to calibrate with the pH 7 solution. If you use something else to calibrate, how would you count for the difference when measuring pH?

I think it's bound to create problems, so my recommendation is to stick to 4 and 7.

I use from https://www.growthtechnology.com/product/ph-buffer-4/ as I can find it in 250 ml bottles for a reasonable price. I don't know if you have them available or something similar.

 

[beervoid]

Ok cheers!

 

[IslandLizard]

IMO, you can use any buffer solution, as long as you can tell your meter to use that different pH instead of the one it expects/flashes. IIRC the 4.01 and 7.01 are NIST buffers, and tend to run much more $$ than regular 4.00 and 7.00 ones, which are fine for our use.

From the instructions with my meter it looks like one can reuse calibration buffers 10x before replacing them with fresh ones. As long as you don't contaminate them. I keep the samples in clear plastic 35mm film canisters that have a very well sealing lid.

I have a few 500ml bottles of buffer solution that are quite a few years old, I got them from a lab. They are still perfectly fine. I checked them against fresh buffers and are spot on. So they withstand the test of time much better than they make you want to believe (at least those do). Even the 10.00 is still spot on.

 

[day_trippr]

^Interesting.^ Meanwhile the 4.01 and 10 NIST buffers I bought in 2017 and have kept in their original bottles have drifted considerably - the 4.01 is now 3.89 and the 10 is ~ 9.85. Which was driving my Hach PP+ batshit. Ordered new buffers last night...

Cheers!

 

[ajdelange]

Better meters allow the use of any buffers you like. You just tell it what buffers you have. Many of the better ones have buffer recognition and can tell automatically which buffer set is being used. I believe the Hach pen meters have this capability. I don't think the Milwaukee ones do - certainly not the MW101. If you can get the seller to take it back in trade for a MW102 I'd definitely do that but that won't, IIRC, get you automatic buffer recognition. Finally, you can calibrate a meter that thinks it's getting NIST traceable technical buffers (4.01, 7) with NIST (6.86 and 7) buffers. You have to do some simple math to correct the readings. This is a PITA but you could put together a simple spreadsheet to do the calculation. Finally, if your meter displays mV (and I don'y think either the Hach ot Milwaukee ones do) you can put together a simple spreadsheet that does the calibration and then lets you enter mV (and temperature) sample readings which it converts to pH.

I also am of the opinion that the NIST traceable technical buffers are much less expensive than the NIST buffers as they are so much more commonly used. OP must be overseas.

 

[IslandLizard]

Again, thanks for the clarification and workaround methods, AJ!

OP must be overseas.

Yup, in another thread he mentioned to live in a remote area somewhere in Asia. Getting supplies is difficult, apparently.

 

[ScrewyBrewer]

Hello,

I just got my mw101 and it comes with a 4.01 and 7.01ph buffer solution.
Ive been looking around to order some more packages but the more economical option available is a 6.86ph solution.
Could I use this for my mw101 to calibrate it or should I go with the same 7.01ph that came with the device.
Thank you

My Hanna meter has settings for either 4 and 7 or 4.01 and 7.01 calibration. I always use the later though.

 

[beervoid]

Again, thanks for the clarification and workaround methods, AJ!

Yup, in another thread he mentioned to live in a remote area somewhere in Asia. Getting supplies is difficult, apparently.

Yep, I have to resort to ordering from ali which mostly carries 6.86 solutions.

Cheers everyone for the responses.