Conductivity Probe is reading too high

[sfboarders]

My conductivity probe is not reading correctly. It's about 5 PPT too high. Take a look at my data log below. I can't get it to read normal after numerous times calibrating with 53ms calibration fluid. I tested my water with a refractometer and it's 35 PPT. Even tested the water in my QT (separate system) and the water in my 55 gallon drum which has always been 35 PPT.

I treated my tank for red bugs the night before and had my UV off, airline out of my skimmer and removed carbon. Around the time it shot up I must have been doing a WC and turning everything back on.

My temp probe has also been connected to PM2 but did not enter temperature compensation if that matters any. That's because I don't know what to set it at.

Any help would be greatly appreciated.

07:00 11/25/2010 20.6 7.98 000 01.4 37.0 76.4 00.8
07:10 11/25/2010 20.6 7.98 000 04.5 36.7 76.1 01.3
07:20 11/25/2010 20.6 7.98 000 04.5 36.6 75.8 01.3
07:30 11/25/2010 20.6 7.88 000 04.6 46.3 75.7 01.3 <----SPIKE Salinity HIGH ph Dropped
07:40 11/25/2010 20.5 7.88 000 04.6 46.7 76.6 01.4
07:50 11/25/2010 20.7 7.89 000 04.6 46.8 77.0 01.3
08:00 11/25/2010 20.5 7.88 000 04.6 46.7 77.0 00.0

 

[schwaggs]

I would use temperature compensation if I were you. I calibrated mine and it is right on at 32.7-32 PPT all day long. I used a temperature compenstion value of 2.4 and that is working good for me. I would recalibrate this way:

Enable temp compenstaion

Bring your calibration solution to the temperature of your tank by floating the package in the tank for 15 minutes.

Place the calibration solution package and the PM2 temp probe into a container of tank water (I used a quart measuring cup I have in my fish room) to keep the solution and temp probe at the same temp.

Calibrate the probe per the instructions.

Also, make sure there are NO AIR bubbles getting into the probe. Mine went way off when it was in an area with air bubbles in the water.

 

[sfboarders]

I tried what you suggested but now it reads 12PPT off. Is there a way to reset the PM2? WC are a normal routine for me. I wonder if there's something in the interceptor that messed my probe up???

 

[schwaggs]

Try gently swishing the probe to make sure there are no bubbles in the probe. If that doesn't fix it, I would give Neptune a call on Monday.

What do you mean by reset it? Pulling the AquaBus cable and plugging it back in will reset the PM2. Running the calibration prodecure will reset the calibration. Not sure what else you would need to reset...

I doubt intercepter can harm the probe.

 

[sfboarders]

Thanks schwaggs. I got another problem with my Apex now. It's display is so dim I can barely see it. I did a restart and I got the same result. Also played with the dimness and it's said to 20 which is the highest.

 

[macktab]

Wonder if a probe cleaning will help. I have had an american marine salinity meter. Manufacturers instructions say "The electrode should be cleaned every few months with a mild solution of water (16 oz.) and dishwashing detergent (1/2 teaspoon). Rinse the electrode well with fresh water." Of course - follow your manufacturers directions.

 

[sfboarders]

Still having the problem with my conductivity reading high. Spoke to Curt and he recommend that I soak the probe in vinegar for 12 hours. Did that and still read high. Even bought a new bottle of 53ms solution to calibrate my refractometer and the probe. Calibrated several times using temperature compensation and floating the solution bottle in the sump to equalize the temp.

I'm thinking the probe is busted.

 

[frankyboy50]

Here is my recent experience to calibrate my PM2 coductivity probe, I had the same issue you have.

First rince probe with ro/di water.

Then blow in to the probe tip, remove as much water you can, do not try to shake it as I did, you will break small glass inside. Let it dry for a while, an haft an hour.

I use calibration liquid from Pinpoint, 53mg, the same for my spectrometer, to calibrate the probe. What I do is take my wife hair dryer, and dry out more the probe, and use it to warm up the calibration liquid to 78 F.

After folow the Apex procedure to calibrate.