Understanding Broadley-James’ FermProbe pH Electrode Range

You may have questions about the Broadley-James FermProbe pH Electrode range, so here we have compiled some of our most frequently asked questions to help assist you.

How do I select a FermProbe pH electrode?

We have three types of electrode and each has different features that are suitable for specific uses.

FermProbe® pH Electrodes with T-Pull® Cap:

  • Strong T-Pull cap eases electrode removal.
  • Greatly reduces cable fatigue.Model F615 phFermoProbe electrodes with T-pull cap
  • Electrode retainer nut is part of the handle so cannot be lost.
  • Standard S8 detachable cable connection.
  • Available in both disconnect cap and integral cabled versions.

FermProbe® pH Electrodes with Standard S8 Metric Cap:

  • Standard S8 detachable cable connection.
  • Polymer disconnect cap with metric Pg13.5 threads.
  • Compatible with European designed bioprocess housings.

FermProbe® pH Electrodes with K9 Metric Cap:

  • K9 detachable cable connection
  • Polymer disconnect cap with metric Pg13.5 threads.
  • Compatible with European designed bioprocess housings.

You can find further information on this topic, here.

How do I match pH Electrodes to Housings?

Both housings and pH electrodes are available in a variety of lengths. This assists operators to select the optimum insertion length. The housing ordering information box lists the suitable electrode models and lengths for each housing style.

However, there is also another way to match electrodes to housings. Each housing length is given a letter classification; ‘A’, ‘B’, ‘C’ etc. Each electrode length is also given a letter classification. Therefore,  any ‘A’ pH electrode will fit any ‘A’ housing listed in the catalogue.

You can find further information on this topic, here.

What is the difference between the pH electrode cap styles?

There are three types of pH electrode cap styles each with specific benefits.

T-Pull Cap:

  • Eases removal of electrode from housing with no tools required.
  • Reduces cable fatigue.
  • The electrode retainer nut is part of the handle so it cannot be misplaced.
  • Also available with integral cable.

Standard S8 Metric Cap:

  • Compatible with nearly all European designed bioprocess electrode housings.
  • Steam sterilizable as well as autoclavable.
  • First choice of use with small autoclavable vessels.
  • Available in a variety of lengths for a variety of requirements and applications.

K9 Metric Cap:

  • Metric threaded cap is compatible with nearly all European designed bioprocess electrode housings.
  • Steam sterilizable and autoclavable.
  • First choice for use with small autoclavable vessels.
  • Available in a variety of lengths for different insertion length requirements and applications.

You can find further information on this topic, here.

Why choose a longer electrode length?

Different electrode lengthsIn some instances, the tank wall can often become coated with a layer of viscous materials which does not mix well with the rest of the media. There is a chance that if the pH bulb of the electrode is located just a few inches inside the tank wall, it may become smothered by the viscous layer. As such, any subsequent pH reading made not represent the bulk of the media in the rest of the tank.

The solution is to choose an electrode and matching housing that extends further inside the tank. This will then position the pH sensing bulb away from the tank wall and so place it closer to the media inside the tank. The subsequent pH measurements will now be much more representative of the media.

You can read further information on this topic, here.

How should a pH electrode be installed?

All pH electrodes and DO sensors can be mounted vertically, as well as on large vessels via a side port. For a side-entry installation, the probe must be at least 15° above horizontal. This incline is enough to prevent bubbles from getting stuck at the tip of the sensor which would prevent the sensor from operating correctly.

You can read further information on this topic, here.


If you have any further queries, please feel free to take a look at our FAQ page. It offers information on a wide variety of topics such as probes, transmitters and measurements. If you cannot find the answer to a specific question, please feel free to contact us and we will assist in any way we can.