Seedling issues PLEASE HELP

[xtsho]

Milk is not guaranteed to be pH 6.6. It can range from that number considerably. Get some actual 7.0 pH calibration solution. That's the only way to accurately calibrate a pH pen.

 

[sarahJane211]

Milk is not guaranteed to be pH 6.6. It can range from that number considerably.

You're wrong.
Dairies aren't allowed to sell pasteurised milk outside the range 6.5-6.7.

 

[TreeFarmerCharlie]

But with that said, if milk is 6.6PH and mine is 6.3ph, that would mean it’s within .3ph of reading... so I’m unsure how that isn’t a good way to do it? I agree it’s better to calibrate it but this way should work I believe.

The reason you can't do this is because the meters measure pH using a calculation based on offset and slope. When you calibrate it, it measures the mV reading between the probes at the specified pH. It then performs a calculation of mV it rads in the fluid you are testing against the calibration mV. You can't just take a miscalibrated pH meter and add to that miscalibration. It's also worth noting that pH readings are logarithmic so every full number. For example, a pH of 6.0 is tens times as acideic as pH 7.0.

 

[TreeFarmerCharlie]

You're wrong.
Dairies aren't allowed to sell pasteurised milk outside the range 6.5-6.7.

People live in different countries with different regulations.

 

[xtsho]

You're wrong.
Dairies aren't allowed to sell pasteurised milk outside the range 6.5-6.7.

No I'm not. Milk straight from the cow might fall within that range but pasteurized milk which is what most people buy at the grocery store could be lower or higher. 6.6 is just the industry standard and not mandated by the FDA.

Using a proper calibration solution is the proper way to calibrate a pH pen. Using milk is not an accurate way to calibrate a pH pen. You yourself even say it could be between 6.5 -6.7 which is a range of 0.3 and not accurate at all.

"The pH of a glass of cow milk ranges from 6.4 to 6.8. Milk fresh from the cow typically has a pH between 6.5 and 6.7.

Milk and Dairy Products: pH of milk is around 6.8 and it is tested for impurities and signs of infection upon collection as well as at point of delivery. In processes such as sterilization, pH is checked since a lower value helps to speed up the process. However, lower pH levels can indicate that the cattle carried leukocyte infections such as mamites.

Milk — pasteurized, canned, or dry — is an acid-forming food. Its pH level is below neutral at about 6.7 to 6.9.

milk has a pH of around 6.5 to 6.7"

 

[TheWizZ]

The reason you can't do this is because the meters measure pH using a calculation based on offset and slope. When you calibrate it, it measures the mV reading between the probes at the specified pH. It then performs a calculation of mV it rads in the fluid you are testing against the calibration mV. You can't just take a miscalibrated pH meter and add to that miscalibration. It's also worth noting that pH readings are logarithmic so every full number. For example, a pH of 6.0 is tens times as acideic as pH 7.0.

Thank you! I will definitely calibrate my meter.