pH meter What am I doing wrong?

[Aeb1419]

I keep trying recalibrate my pH meter using my profilux and I keep getting a different reading from my Hanna checker. Not sure which is actually more acurate. At first I thought it was the reagents from GHL which I got used. At that time there was about a .3-.4 discrepancy. Now after recalibrating using lab grade solutions its off by a little more. I have the Milwaukee MA911B/2. It was recommeded to me and I got it brand new.

 

[saltypepper]

Silly question but do you know the Hanna is right? Is it recently calibrated?

 

[Aeb1419]

Silly question but do you know the Hanna is right? Is it recently calibrated?

I do not. I didnt even know it can be calibrated.

Will look it up thanks

 

[gbroadbridge]

I do not. I didnt even know it can be calibrated.

Will look it up thanks

The Hanna cannot be calibrated. It can be tested against a reference to check it is functioning correctly.

Its stated accuracy is +- 0.2pH

If you've calibrated the Profilux using pH 7 and 10 buffers or similar it is probably accurate to within the same range, so if the difference is less than 0.5 they're both correct.

It really doesn't matter, either reading is fine.

 

[Aeb1419]

The Hanna cannot be calibrated. It can be tested against a reference to check it is functioning correctly.

Its stated accuracy is +- 0.2pH

If you've calibrated the Profilux using pH 7 and 10 buffers or similar it is probably accurate to within the same range, so if the difference is less than 0.5 they're both correct.

It really doesn't matter, either reading is fine.

Thanks. I just worry because in the future I plan to dose and would like to know if my pH is going to high or not.

Plus im doubtful because I dont dose and Im confused if my pH is actually 8.4. I am doing nothing to achieve that. And the fact thats my actual goal for pH, worries me that it might not be accurate and I eithet dont dose thinking its correct, or dose to much and get close to 9.

 

[Reef.]

Ph is notoriously hard to test with any accuracy, ph testers can cost thousands and the probes need replacing often, I have little faith that a hanna checker that costs $70 and can not be calibrated is going to be reliable.

 

[Randy Holmes-Farley]

Thanks. I just worry because in the future I plan to dose and would like to know if my pH is going to high or not.

Plus im doubtful because I dont dose and Im confused if my pH is actually 8.4. I am doing nothing to achieve that. And the fact thats my actual goal for pH, worries me that it might not be accurate and I eithet dont dose thinking its correct, or dose to much and get close to 9.

It is unusual to dose and have pH get high, unless you dose a lit at once.