Variations between meters

marzig

marzig

Well-Known Member
I just got a complete and identical Apera pH/EC meter to have for a back up. I replaced the probe on my original as it was close to 2 years old 3 months ago. After cleaning and calibrating them both I decided to compare their readings. The temp, EC, and ppm are very close between them. But there is some difference in the pH readings and I'm wondering what's acceptable.

For instance 5.81 and 5.88. In my mind those are 5.8 and 5.9 rounded to the nearest 10th. In my work before retirement, I did a large amount of machining where tolerances of a 0.001" were critical so a 0.100 or 0.010 of an inch difference was huge.

Am I being to fussy or is the difference between 5.8 and 5.9 acceptable?
 
D

Delps8

Well-Known Member
You're not being fussy. The fact that you notice it and question it is it because that's who you've become.

"In my work before retirement, I did a large amount of machining where tolerances of a 0.001" were critical so a 0.100 or 0.010 of an inch difference was huge."
Understood (heh, we're the same age!). You made a living, for decades, by working to that standard. It's going to take time and effort to be able to compartmentalize that.

Repeat after me - "It's just a plant."

I'm a former artillery officer and have been a software engineer for 30+ years so, to me, it's either right or wrong. And it can't be "good enough, it has to be excellent. Oops, I mean "it's just a plant". ;-)

It took a while for me to accept that but, yeh, it's just a plant so 5.8'ish is good.

And I use a pH doser to keep it at 5.8 but that's because the doser makes it one less thing to deal with.
 
marzig

marzig

Well-Known Member
Delps8 said:
You're not being fussy. The fact that you notice it and question it is it because that's who you've become.

"In my work before retirement, I did a large amount of machining where tolerances of a 0.001" were critical so a 0.100 or 0.010 of an inch difference was huge."
Understood (heh, we're the same age!). You made a living, for decades, by working to that standard. It's going to take time and effort to be able to compartmentalize that.

Repeat after me - "It's just a plant."

I'm a former artillery officer and have been a software engineer for 30+ years so, to me, it's either right or wrong. And it can't be "good enough, it has to be excellent. Oops, I mean "it's just a plant". ;-)

It took a while for me to accept that but, yeh, it's just a plant so 5.8'ish is good.

And I use a pH doser to keep it at 5.8 but that's because the doser makes it one less thing to deal with.
Click to expand...
It's just a plant, It's just a plant.

Thanks!
 
futurebanjo

futurebanjo

Well-Known Member
I'm the most anal person youll meet when it comes to this kind of stuff... I keep a spreadsheet, and I test PH with my stick, litmus paper and liquid.
I then take an average of those 3 readings.

I need to relax.

Having a range of fluctuating PH is fine... good, even, as long as it doesn't swing too far in either direction.
 
D

Delps8

Well-Known Member
futurebanjo said:
I'm the most anal person youll meet when it comes to this kind of stuff... I keep a spreadsheet, and I test PH with my stick, litmus paper and liquid.
I then take an average of those 3 readings.

I need to relax.
Click to expand...
You've got me beat!


futurebanjo said:
Having a range of fluctuating PH is fine... good, even, as long as it doesn't swing too far in either direction.
Click to expand...
Agree completely.
 
marzig

marzig

Well-Known Member
futurebanjo said:
I'm the most anal person youll meet when it comes to this kind of stuff... I keep a spreadsheet, and I test PH with my stick, litmus paper and liquid.
I then take an average of those 3 readings.

I need to relax.

Having a range of fluctuating PH is fine... good, even, as long as it doesn't swing too far in either direction.
Click to expand...
Well I don't feel too bad now, I only use a meter but I do keep a spreadsheet lol.
 
D

Delps8

Well-Known Member
marzig said:
Well I don't feel too bad now, I only use a meter but I do keep a spreadsheet lol.
Click to expand...
I switched to a doser but I log the run time of the doser.

I keep a grow journal in Excel. It has come in really handy. Below is a sample from my Spring 2024 grow:

Excel calculates these values based on the date.
82= day number above ground
11.5 weeks
35 days in flower

I mucked up this grow—I was adding H2O2 to the humidifier to stop algae from growing and, like a fool, I didn't realize that I was adding enough to stunt the plant until it was too late. I refer to it as my Claus von Bulow grow.

I've used this format since I started growing in 2021 and since I only do grows in the Spring and Fall (too hot here in SoCal in the summer), it's very helpful in getting a grow running.

1722043342739.png
 
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