Milwakee MW102 vs Ward's, who is correct?

[fendersrule]

My water report has a pH of 7.4.

Just got my Milwaukee MW102 in the mail.

Noticed that there was crystals around the probe cap. Normal for the storage solution. Removed it (which doesn't slide off very easy by the way) and calibrated it to the instructions with the 7.01 and the 4.01 (or whatever it is) solutions.

Ran warm tap water for a minute into a glass. Stuck the probes in and gently stirred. 7.25.

Hmm, I thought. 7.25 vs 7.4 is quite an accuracy difference.

Recalibrated again with the solutions.

Still got 7.25-7.26.

So is my PH 7.26 or is it 7.4? That will affect my BrunWater input.

Edit, it doesn't look like Brunwater cares if my reported PH is 7.26 or 7.4. It's the Bicarbonate number that determines the Mash pH level.

So 7.26 or 7.4, doesn't matter, my reported HCO3 is still 128 either way.

 

[day_trippr]

[...]Edit, it doesn't look like Brunwater cares if my reported PH is 7.26 or 7.4. It's the Bicarbonate number that determines the Mash pH level.[...]

You preempted a barrage of responses saying exactly that

As for the MW102, try soaking the sensor in the storage solution for a few hours to a full day then try calibrating again...

Cheers!

 

[IslandLizard]

A water report is a snapshot. When was that taken?
Did you use the exact same water for your water report as for your pH meter test? Or were there several days or weeks in between?

Why warm water?

 

[fendersrule]

Hmm. Doesn’t the probe cap come in the storage solution, therefor, already submerged?

 

[fendersrule]

A water report is a snapshot. When was that taken?
Did you use the exact same water for your water report as for your pH meter test? Or were there several days or weeks in between?

Why warm water?

A month away. Not exact same. I have reason to believe the MW is accurate because it correctly reads the calibration solutions...

 

[IslandLizard]

A month away. Not exact same.

So why are you surprised the readings aren't exactly the same?

Your water supply source varies in content, sometimes more than others. Smaller or larger deviations from an average are to be expected.

Why did you use warm water for this test? Is that what you sent to Ward too?

 

[fendersrule]

Cancel that, I lied. It reads the 7.01 as 6.99.

It reads 4.01 as 3.85.

So much for buying an expensive tool.

 

[Silver_Is_Money]

Clean the probe and let it sit in fresh storage solution for at least a full day. Then calibrate. Then take all pH readings at close to 77 degrees F.

 

[IslandLizard]

Cancel that, I lied. It reads the 7.01 as 6.99.

It reads 4.01 as 3.85.

So much for buying an expensive tool.

Back to this first:

As for the MW102, try soaking the sensor in the storage solution for a few hours to a full day then try calibrating again...

You can make your own storage solution. It's most likely a 3M or 4M Potassium Chloride solution. Double check.
AlphaChemicals sells KCl.

 

[day_trippr]

Hmm. Doesn’t the probe cap come in the storage solution, therefor, already submerged?

You didn't note the probe was immersed, just that there were crystals around the cap - which usually indicates the solution has dried out...

Cheers!

 

[fendersrule]

I may have "cross pollinated" the solutions too. I didn't think to "blow" off the tip, I just did a rinse + soft tissue wipe + gentle shake during calibration. I can proceed to soak it overnight and try calibrating again if I trust my fluids still.

Also, the blue grip actually "unscrews" to relieve tension to be removed. I didn't know that...before I was just yanking and twisting on it. I'm not that stupid and it would have been nice for them to call that out in the instructions or mold an arrow onto it. That's an easy way to damage the probe by not doing that.