pH meter keeps drifting off

I have a Bluelab Combo Meter and kept getting a value that drifts like the next day after calibration. The probe was over a year old so I replaced it.

The new probe is doing the same thing.

I have a doser and the doser will read 6.0 and my combo will read 6.2

I dip them both in the same 7.0 calibration solution and they both say 7.0

Not sure wtf is going on.

Any suggestions?

Yer ferts are buffers just like water from a tap, you can set any ph but a buffer moves it.

As basic chemistry ph some tap water to 4.2 you have now ionized and broken the carbonate and most alkakine buffers.

Chemistry isnt fun until you grow weed, then its the answer to this question

Ph is pretty irelevant, buffering is everything

And somthing about co2 and carbonic acis but thats not much idk.

firsttimeARE said:

I have a Bluelab Combo Meter and kept getting a value that drifts like the next day after calibration. The probe was over a year old so I replaced it.



Any suggestions?

Click to expand...

close enough
worry about something else, just remember that the one reads .2 higher than the other one.

A 0.2 difference isn't a lot between two different instruments. I have 3 different temp/rh meters in my grow room and tho the temps are very close the rh is about a 10% spread so I split the difference and call it good.

If it was a full point apart I'd be concerned but close enough.

My bad i think i read that wrong and was responding to the next day drift.

If you want better accuracy spend a few hundred bucks more on a meter, my bluelab is good but prone to a small swing.

Just baffles me that they calibrate correct from same solution, yet one measures my water differently

Since my combo is always off once I recalibrate I'm trusting the doser reading.

I've calibrated this replacement probe over 8 times in the past month and it's a stubborn bitch.

In my DWC systems I'm not worried cause I use a swing.

But my starter cubes and coco is a set feeding and that's what they get. I guess I could feed them 5.5 one day. 5.8 the next and 6.1 the next just to make sure it's getting all nutrients

Ye

firsttimeARE said:

I have a Bluelab Combo Meter and kept getting a value that drifts like the next day after calibration. The probe was over a year old so I replaced it.

The new probe is doing the same thing.

I have a doser and the doser will read 6.0 and my combo will read 6.2

I dip them both in the same 7.0 calibration solution and they both say 7.0

Not sure wtf is going on.

Any suggestions?

Click to expand...

I was thinking about getting the combo meter but Ive heard people say to buy the ph and ec pen separately.
Ive had my bluelab ph pen for over 2 years and still works great! The ec pens on the other hand seem to break at around a year. Moral of the story buy them separatly next time.

Thegermling said:

Ye

I was thinking about getting the combo meter but Ive heard people say to buy the ph and ec pen separately.
Ive had my bluelab ph pen for over 2 years and still works great! The ec pens on the other hand seem to break at around a year. Moral of the story buy them separatly next time.

Click to expand...

Their truncheon is bulletproof.

I had the pH pen. I got tired of bouncing between two meters. Also my pH pen lasted about a year and a half. I like being able to change probes rather than throwing it away. Probes usually last me a year to 18mo.

firsttimeARE said:

Their truncheon is bulletproof.

I had the pH pen. I got tired of bouncing between two meters. Also my pH pen lasted about a year and a half. I like being able to change probes rather than throwing it away. Probes usually last me a year to 18mo.

Click to expand...

I need precise ec readings even though their ec pen only has 10ppm increments instead of 100ppm of that truncheon. I still prefer that ec pen. I like the replaceable probe of that combo meter but Idk if id buy it still.

The old yellow $10 fleabay ph pens are alright, got a $100 ph metre i don't even use.