pH meter won't caliberate

!!!

Now in technicolor

Veteran

• Oct 23, 2009

• #1

It's a Hanna HI 99104 pH meter. It has 2 dials for calibration. One for 7 and one for 4/10.

I have new calibration liquid. I dip pen in pH 7 and adjust the "7 trimmer" to 7.01 (the exact pH of that liquid at that temp).

but when I put the pen in the pH 4 solution, I cannot bring the pH lower than 5.5 by adjusting the 2nd (4/10 pH) trimmer.

If I adjust both the 7 and 4 trimmer, I can fix up the pH, but then if I put the pH pen back into the pH 7 solution, the pH is off on that and won't be able to go back down to 7 unless I adjust the 4/10 trimmer as well.

Basically - it won't calibrate! It's not too old but has only been used about twice, got it brand new before that. The electrode dried up during storage (months) though.

 

C

coconaut

• Oct 23, 2009

• #2

Did you try re-hydrating the electrode with a proper storage solution?
I would suggest soaking the electrode and bulb in storage solution for a couple hours.

 

M

milehighmedical

• Oct 23, 2009

• #3

I hate PH meters for exactly this reason. This round I'm not using one at all and so far there's no complaints.

 

B

bicyclebenny

Active member

• Oct 23, 2009

• #4

I had the same issue. I emailed Hanna and told them the methods I used to try to calibrate it as you've described. They replaced the probe for free.

 

FreezerBoy

Was blind but now IC Puckbunny in Training

Veteran

• Oct 23, 2009

• #5

pH pens are a crapshoot at best. Of the pens, Milwaukee sucks the least followed by Oakton while Hanna scrapes the bottom of the barrel. A $5 test drop kit from the aquarium store is all you need.

 

mean mr.mustard

I Pass Satellites

Veteran

• Oct 23, 2009

• #6

unless your solution is really dark... then it's totally useless.

 

FreezerBoy

Was blind but now IC Puckbunny in Training

Veteran

• Oct 23, 2009

• #7

Strips will do for that. pH pens are toys and I wouldn't trust one farther than it could throw me and I'm a skinny guy.

 

D

dongle69

• Oct 24, 2009

• #8

How do you compensate for temperature with strips or drops?
Is there a chart that you go by?
Even without a way to compensate for temperature, strips and drops are only a rough estimate of ph.
A meter is the only way to get accuracy.
A meter, when treated properly, will last for years.

 

odin_

Member

• Oct 24, 2009

• #9

FreezerBoy said:

Strips will do for that. pH pens are toys and I wouldn't trust one farther than it could throw me and I'm a skinny guy.

Click to expand...

what about when the strip goes in and comes out in between colours

then another one goes in and is completely different shade between colours?

pens suck too, but unless i had the shittiest strips ever, they suck worse

 

C

coconaut

• Oct 24, 2009

• #10

I've had my [barrel-scrapping] hanna for 4 years, it's still calibrated perfectly. I wouldn't do without it. Proper use and proper storage when not in use is key.

 

!!!

Now in technicolor

Veteran

• Oct 24, 2009

• #11

The calibration solution (7 + 4) cost about $30 at the hydro shop and the meter itself was about $30 on ebay. What a waste. While I do still need a more accurate meter for other purposes, for this hobby I just ordered 400 pH strips for $7 shipped (ebay). I wish I had done that before dropping $60 on this Hanna POS. I'll try calling them.

 

M

Mickymouse

Member

• Oct 24, 2009

• #12

dongle69 said:

How do you compensate for temperature with strips or drops?
Is there a chart that you go by?
Even without a way to compensate for temperature, strips and drops are only a rough estimate of ph.
A meter is the only way to get accuracy.
A meter, when treated properly, will last for years.

Click to expand...

Dont need to be that accurate some drift is good.

 

odin_

Member

• Oct 24, 2009

• #13

Mickymouse said:

Dont need to be that accurate some drift is good.

Click to expand...

then why test?

unless your tap water is really bad it will always be close...

 

D

dongle69

• Oct 24, 2009

• #14

Drift is good, but the drops/strips can be off by an entire point (or more), which can put your ph below 5 or above 7, and that is not good.

 

M

Mickymouse

Member

• Oct 24, 2009

• #15

If your below 5 or above 7 you will know with drops.Unless your color blind.

 

Mist

Member

• Oct 24, 2009

• #16

I just picked up a Hanna Champ which is probably the cheapest of their PH pens and it has worked great. I calibrated it and then tested the nutes and retested using my PH drops and vial and everything looked good.
I mainly bought it so that I could see a more accurate reading as opposed to trying to decide which shade of yellow was best. What I found out was that I had been keeping my nutes at 6.0 all along and now the wife is mad that I spent the $45.00 on the ph pen, LOL! I just wasn't trusting my old eyes anymore and needed some validation is all. $45 bucks seemed like a cheap resolution when there are thousands of dollars on the line.



Happy Growing.

 

O

ourcee

Active member

• Oct 24, 2009

• #17

milehighmedical said:

I hate PH meters for exactly this reason. This round I'm not using one at all and so far there's no complaints.

Click to expand...

I use droppers now, I know the pH is being read correctly but then when I try to calibrate my electronic hannah one to the dropper, I can't even turn the dial enough.

screw the electronic ones, lost a crop due to assuming technology wouldn't fail. lessons learned.

 

O

ogatec

• Oct 24, 2009

• #18

join the club. my meter has been out of action for 2 weeks now for warranty work, i forgot how easy and cheap drops were....im on the sunleaves brand, wide range & only have to use 1 drop instead of the normal 2-3. i think i paid $7 total

 

S

SmokyMtnToker

Member

• Oct 24, 2009

• #19

I have a Hannah constant monitoring unit and I think it needs calibrating as well. RO water I bought read about a 3...is that possible? The instructions say to get the unti to the function for calibration and then stick the probes into the little packets that came with the thing...one at a time. I will try it and see what happen. The unti is supposed to calibrate automatically, so how does one tell when it is not doing it anymore? I am so frustrated with hydro I am tempted to sell my new Aerojet 24 site aeroponic unit and stay with soil...it is all too complicated.

 

D

dongle69

• Oct 24, 2009

• #20

Mickymouse said:

If your below 5 or above 7 you will know with drops.Unless your color blind.

Click to expand...

That is why I mentioned that their accuracy can be far off.
If they read 5.5, they could actually be 4.5 or 6.5 because of their margin of error, color blind or not.
...and if you have humic/fulvic acid in your nutrients, which makes the water brown/darker, the drops are rendered completely useless.
They also do not compensate for temperature like a good meter does.
That being said, any off this stuff can be faulty.... meters, drops, or strips.
My meter (Hanna combo 98129) is going on 4 years now, but I treat it right.
I deal with 5 different reservoirs and I need something that can keep up with me.