Warning - Calibrate your pHep HI98107

I'd be interested to hear from other Hanna pHep HI98107 pH meter users.

I bought one a couple of months ago, along with storage solution, cleaning solution and pH7.0 and pH4.01 buffer solutions.
I've followed all of their instructions to the letter, but find that the meter offset goes out by up to 0.4 in a week and the slope goes out by 0.1pH . (Measures 7.0 buffer as 7.4 and 4.01 buffer as 4.1.)
Bloody annoying and lucky I used my indicator solution to check.

At the moment, I only mix a batch of nutes once a week and have to calibrate the meter every time before use.

Any comments, suggestions?

 

Thanks, GreenRevenger, for the feedback.
So, it's not just my meter.
I checked the Hanna website, in their FAQ, for answers. One regularly asked question was "How often do I need to calibrate my pH meter?" Hanna avoided the issue and said something like "That depends on .... etc." No real answer. I suspect that the meter will never settle down and may need calibrating every use forever.
For anyone not checking and re-calibrating regularly, this could totally fuck up a grow. Having a meter that you think is right can breed a false sense of security.
I'm not overly impressed and will probably go back to my indicator solution for reliability.

Any other HI98107 users have input?

GreenRevenger, I might have to look at buying an Oakton meter.

 

Thanks joker865, I'm beginning to form a mental picture of the reliability of these meters. Not good.
As you say, a whole grow could be easily screwed up by relying on the accuracy over time.
I've noticed in my wanderings that many growers swear their pH is either 6.5 or 5.8, for soil or hydro respectively, when it appears obvious that they have a pH issue.
The second time I used this meter, I adjusted my pH, according to it, to 5.8 and decided to double-check with Flairform indicator solution - 5.4. Poison. Nothing has changed since, despite pulling out a new length of electrode, washing with Hanna cleaning solution, using Hanna storage solution when not in use, etc.

Are we doing something wrong, or are these meters rubbish?

I have another friend who bought one of these, (a member), billgee.
I'll ask his opinion as well.

 

You read my mind, Freakbro. I often think that some of my threads are more important than they are, (who doesn't), but I had trouble deciding where to post this, because it could go in any one of a few sections.

So, a question. How do I move it?

(And thank you for the +rep.)

 

Ha, that was me last night. Slept 'til almost midday this morning.

I PMd BUDSLiNGER earlier about the move.

Thanks billgee, for the response. I appreciate it.

All said and done, I reckon that good ol' reliable indicator solution pH test kits are the way to go.
If I was using my meter heaps every day, it might be worth re-calibrating a couple of times a week, but otherwise it's not worth all of the fucking around. To make a once-weekly mix, I'm sick of re-calibrating every time and if I don't I could easily poison the girls.

As Freakbro says, 'this is the major factor in plant health'.

 

I can do it manually, by copying and pasting then enclosing each part in quotes and adding quote=xxx etc to each to include the OP's name.
Is there an easier way?

 

On the subject of this meter, I had some issues a couple of months ago when I first bought it, too, and started a thread on the subject.
It's here:- Hanna pH meter problem

After the issues mentioned in that thread, to then find out that the reading drifts so much so quickly, I definitely wouldn't recommend this model of meter to anyone.
Hanna have a good name, though, so their top-of-the-line meters should be better, I'd imagine.


And Freakbro, I say stick to what you're good at.
You're 'the (bug)man' in the 'Pests...' section. You don't need to be a TECHNOWIZARD.
The only reason I don't frequent it more often is that I've been blessed since switching to coco and have had no pests or real problems to speak of. Keep up the great work.