Any Apex Conductivity Probe Improvements

[Jyetman]

My probe is over three years old and needs to be replaced. Have they improved on these probes or can I expect erratic results as the last one?

[Wiskey]

I'm following this as well because I completely gave up on mine. I felt it was a real waste of money, my salinity readings were all over the place. Now I use it to monitor my Kalk concentration. I'm happy I found that use for it.

Whiskey

[ohashimz]

changed my prob 3 times over the last 3 years. Same issues followed. Also gave up.

[ca1ore]

These probes are still a challenge. Always dread replacing it because I know I’ll have to calibrate it a bunch of times before getting a sensible reading. I just calibrate mine now with tank water which refractometer says is 35. I find it useful as a monitoring device. Don’t use it to control anything though.

[ThRoewer]

I had 2 of these failing on me.

Now, these electrodes are basically nothing more than two platinum contacts. So, unless it gets mechanically damaged or operated on a wrong amplifier, it should last a long time if properly cleaned.

So I instantly had a hunch that the problem must be either with the cable or the connector. It turned out to be the connector or more precisely the solder joints inside the Mini-DIN connector. Whoever soldered these didn't know what he/she was doing and created cold solder joints. It is just a matter of time when these come loose or completely off. On the first electrode both leads had come off, on the second only one lead had come off (not that I would trust the other.)



A cold solder joint could also be one explanation why there are so many people reporting unstable readings or problems to calibrate the electrode.

The good news is that this issue can be fixed without shelling out over $120 for a new electrode if you can solder or know someone who can solder.

There are of course other issues with this electrode. One of them is that air bubbles might get trapped inside and alter the reading.

[Jyetman]

Originally Posted by ThRoewer

I had 2 of these failing on me.

Now, these electrodes are basically nothing more than two platinum contacts. So, unless it gets mechanically damaged or operated on a wrong amplifier, it should last a long time if properly cleaned.

So I instantly had a hunch that the problem must be either with the cable or the connector. It turned out to be the connector or more precisely the solder joints inside the Mini-DIN connector. Whoever soldered these didn't know what he/she was doing and created cold solder joints. It is just a matter of time when these come loose or completely off. On the first electrode both leads had come off, on the second only one lead had come off (not that I would trust the other.)



A cold solder joint could also be one explanation why there are so many people reporting unstable readings or problems to calibrate the electrode.

The good news is that this issue can be fixed without shelling out over $120 for a new electrode if you can solder or know someone who can solder.

There are of course other issues with this electrode. One of them is that air bubbles might get trapped inside and alter the reading.

I'll tear mine apart and check it out. However, its too late saving $125 already bought a new one and installed it. Same problem as others stated fails to calibrate. Don't waste your money on calibration fluid it never comes close! What I finally did was make my own solution using Morton iodized salt, distilled water and a Milwaukee digital refractometer for reference. After 5 attempts on the new pinpoint 53.0 bottle I bought with probe I finally tossed it. Got out the mix I saved from last time and it calibrated perfectly on the first try.

[ThRoewer]

Originally Posted by Jyetman

I'll tear mine apart and check it out. However, its too late saving $125 already bought a new one and installed it. Same problem as others stated fails to calibrate. Don't waste your money on calibration fluid it never comes close! What I finally did was make my own solution using Morton iodized salt, distilled water and a Milwaukee digital refractometer for reference. After 5 attempts on the new pinpoint 53.0 bottle I bought with probe I finally tossed it. Got out the mix I saved from last time and it calibrated perfectly on the first try.

Repair it and keep it as backup.
I usually adjust my tank water to 35 ppt using a good refractometer calibrated with 35 ppt refractometer calibration solution.
Once the tank is properly adjusted I use it to calibrate the electrode.
It's a bit backwards but it works and serves the purpose...
In the end all you want is a reference value to keep the tank at and for that absolute precision is pretty much irrelevant.

Sent from my XT1254 using Tapatalk

[Jyetman]

Originally Posted by ThRoewer

I had 2 of these failing on me.

Now, these electrodes are basically nothing more than two platinum contacts. So, unless it gets mechanically damaged or operated on a wrong amplifier, it should last a long time if properly cleaned.

So I instantly had a hunch that the problem must be either with the cable or the connector. It turned out to be the connector or more precisely the solder joints inside the Mini-DIN connector. Whoever soldered these didn't know what he/she was doing and created cold solder joints. It is just a matter of time when these come loose or completely off. On the first electrode both leads had come off, on the second only one lead had come off (not that I would trust the other.)



A cold solder joint could also be one explanation why there are so many people reporting unstable readings or problems to calibrate the electrode.

The good news is that this issue can be fixed without shelling out over $120 for a new electrode if you can solder or know someone who can solder.

There are of course other issues with this electrode. One of them is that air bubbles might get trapped inside and alter the reading.

How did you remove the sleeve cover on connector end?

[ThRoewer]

Pry it off with a small flat screwdriver. If you look at the connector from the front you will see where the separation line is. You will have to go once around the diameter to expand the sleeve a little (if it doesn't return on its own this can be readjusted with a hairdryer) to get it ultimately out.
On the first one I took apart I just sliced it open, but that isn't necessary. Though if you chose to go that route, the connector is readily available at Amazon: https://www.amazon.com/Male-Pin-Mini.../dp/B000LFVFOY
The image may also help you to understand how to get the sleeve off: