pH meter questions

Water Orchids

A
Water Orchids

  • 0
  • 0
  • 6
Life Ring

A
Life Ring

  • 0
  • 0
  • 9
Fisherman's Rest

A
Fisherman's Rest

  • 5
  • 2
  • 47
R..jpg

A
R..jpg

  • 3
  • 0
  • 65
WPPD25 Self Portrait

A
WPPD25 Self Portrait

  • 9
  • 3
  • 121

Recent Classifieds

Forum statistics

Threads
197,896
Messages
2,766,570
Members
99,500
Latest member
theSting
Recent bookmarks
0

RalphLambrecht

Subscriber
Joined
Sep 19, 2003
Messages
14,600
Location
K,Germany
Format
Medium Format
I bought a cheap Hanna pH meter and hope to use it for the pool and some darkroom work, such as checking developer pH;I have two questions:
1.Can I calibrate it mixing 5g of Borax in 1 liter of water and assume this to be at pH9.2?
2.In the past I've stored the tip in a strong solution of KCl potassium chloride but the crystals 'grew' all over the meter and the container, making a mess and I lost valuable chemicals.Would a strong solution of Na Cl achieve the same purpose without making the mess?
 

Mick Fagan

Subscriber
Joined
Sep 13, 2005
Messages
4,409
Location
Melbourne Au
Format
Multi Format
Ralph, I have been using the Hanna pHep range of meters for around 20 years. I have found that the life of the electrode in these meters, can be lengthened by using the Hanna storage solution.
https://www.hannainst.com.au/product/HI70300L/Storage+Solution+460ml

Not being that great in chemistry, I was very much in the dark about what exactly was the best way to store the electrode. A chemist friend regularly made a storage solution for me, increasing the life of the electrode from about 2 years to around 3 years.

I then started using the Hanna storage solution, electrode life went to around 5 years. I am currently still running a pHep 3 Hanna pocket meter. It is around 10 years old, I think it is just starting to fail. Last week when I used it after calibration, it started wandering all over the place, this was with fresh batteries. The perfect excuse to upgrade to the pHep 4 meter. This is by far, the longest I have had one of the Hanna pocket pH meters work.

Previously I used Hanna pH 7 (HI 7007), but with my current pHep 3 and the unit before it, I switched to the Hanna storage solution (HI 70300L) and apart from dropping my prior meter onto the floor, electrode first, I have no reason to believe it wouldn’t have had an extended electrode life like my current pHep 3 Hanna meter.

Mick.
 

EdoNork

Member
Joined
Mar 15, 2010
Messages
69
Location
Bilbao
Format
Multi Format
You can simply wash the electrode with distilled water, refill with a KCl 3.5M solution and wet it with the appropriate maintenance solution. A saturated KCl (3.5M) solution is suggested by manufactures. It's the same solution that fills the electrode.
 
Joined
Jan 9, 2011
Messages
154
Location
Kehl/Strasbo
Format
Multi Format
As far as I understand the electrode should be stored in the same solution as the electrolyte solution inside the electrode. For many (but not all) electrodes this is 3M KCl. I think it is not a good idea to replace KCl by NaCl here, because the sodium will diffuse inside the electrode.

I guess a one point calibration with borax is good if you want to measure solutions in this range (e.g. developer).
 

EdoNork

Member
Joined
Mar 15, 2010
Messages
69
Location
Bilbao
Format
Multi Format
Depending on the electrode manufacturer the KCl solution can be either 3M or 3.5M, just check instructions.
 
Joined
Jan 9, 2011
Messages
154
Location
Kehl/Strasbo
Format
Multi Format
It can also be saturated AgCl with 3(.5)M KCl depending on the construction of the pH electrode.
So definitely: check instruction!
 
Photrio.com contains affiliate links to products. We may receive a commission for purchases made through these links.
To read our full affiliate disclosure statement please click Here.

PHOTRIO PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Ilford ADOX Freestyle Photographic Stearman Press Weldon Color Lab Blue Moon Camera & Machine
Top Bottom