Digital Aquatics Salinity Probe Issue

n2585722 · May 23, 2018

It may of had some type of film on it when you calibrated it. The film could have came off after a few hours once it was put back in the tank. When I clean mine it takes several day before I can calibrate it. The reading keeps climbing. Keep and eye on it and see if it continues to climb. Once it is stable try and calibrate it again. I have had the probe I got as a beta unit years ago and it is still working. What are your raw data values at the cal points?

EuroDriver · May 23, 2018

A brief dip shouldn't be a big deal but they do go bad here and there. How old is it? Maybe DA will be willing to RMA it

Bmezz · May 23, 2018

they tell you to put on a nice angle it is difficult to not get under water why wouldnt it be sealed to avoid water damage?

EuroDriver · May 23, 2018

It's sealed with an o ring but it's not bulletproof. There's a water level marker near the top. It's best to keep the water level below that

n2585722 · May 24, 2018

I have never seen a water marker on the one I have. Are you sure about that?

Bmezz · May 24, 2018

i looked as well and no marker..

n2585722 · May 24, 2018

Just remember that the salinity probe is actually a conductivity probe. That means it it measuring the resistance of the water over a specific distance. The more salts the lower the resistance of the water or the higher the reading. Anything in the water that affects the current flow between the two contacts in the tip will affect the reading most likely raising the resistance which will lower the reading on the controller. So organisms in the water can accumilate in the probe tip and cause an error in the reading. I would not calibrate just because of a drop in the reading which is the most common occurrence. Try cleaning the probe in some Di water mixed with vinegar like you use to clean pumps. After cleaning place back in the tank water and wait a few days before calibrating. During that time keep an eye on it to see if the readings stop trending up. Also the wire to the probe will not hold up to being submerged long term. It will get stiff and crack. It should not be an issue getting it wet every now and then.

Bmezz · May 24, 2018

n2585722 said:
Just remember that the salinity probe is actually a conductivity probe. That means it it measuring the resistance of the water over a specific distance. The more salts the lower the resistance of the water or the higher the reading. Anything in the water that affects the current flow between the two contacts in the tip will affect the reading most likely raising the resistance which will lower the reading on the controller. So organisms in the water can accumilate in the probe tip and cause an error in the reading. I would not calibrate just because of a drop in the reading which is the most common occurrence. Try cleaning the probe in some Di water mixed with vinegar like you use to clean pumps. After cleaning place back in the tank water and wait a few days before calibrating. During that time keep an eye on it to see if the readings stop trending up. Also the wire to the probe will not hold up to being submerged long term. It will get stiff and crack. It should not be an issue getting it wet every now and then.

Thanks good advise. What's the dilution for vinegar and rodi water?

n2585722 · May 24, 2018

Bmezz said:
Thanks good advise. What's the dilution for vinegar and rodi water?

I usually try for around 50/50.

Bmezz · May 24, 2018

n2585722 said:
I usually try for around 50/50.

Last question how long to soak in that solution for the probe to be effective?

Bmezz · May 25, 2018

Well wierd. In the 50/50 registered almost 0 which makes sense. In the sump back to 334.5. It's funny it's like 34.5 is right and it's 300 off??

n2585722 · May 25, 2018

Bmezz said:
Well wierd. In the 50/50 registered almost 0 which makes sense. In the sump back to 334.5. It's funny it's like 34.5 is right and it's 300 off??

It will not read correctly until it has been calibrated. I would jot down the raw data readings at the calibration points as a reference.

Bmezz · May 25, 2018

n2585722 said:
It will not read correctly until it has been calibrated. I would jot down the raw data readings at the calibration points as a reference.

Calibrate again after the vinegar cleaning? Ok thanks

n2585722 · May 25, 2018

Bmezz said:
Calibrate again after the vinegar cleaning? Ok thanks

Just remember give it a few days to settle. You can calibrate it in the meantime, but it may drift up some more.

Bmezz · May 26, 2018

n2585722 said:
I don't know what the issue was on the pH port. Do you have a way to hook the module to a computer with a SID to see if it has the current firmware? If you can update the firmware if it is not current. You can use PortCalibrate() command with the pH port once you get the raw data readings at 7 and 10. To use port calibrate you will need to know your module number and the port number of the port you are calibrating. To find that pick a unused output and select the controller function then show. Select the input. There are numbers at the left of the different imputs like "3:4" The first number is the module number and the second is the port. I think most of the modules with pH ports it will be port 4 with the exception of the Archon and the second port on the SLX. A port calibrate command is PortCalibrate(Modlue Number port Number,Low Calibrate Point, Low Calibrate Raw Data,High Calibrate Point,High Calibrate Raw Data).

Example: PortCalibrate(3:4,7.00,1050,10.00,-799)

This goes into the command line on the system page. It can also be used to do a two point temprature calibration on the temp ports. It has been awhile since I used this so I am going from memory. Lindsey or Eric if this is wrong then please correct me.

Your salinity raw data is not that far from mine. I did find out if you do a clean on it it is best to wait for several hours before calibrating it. I calibrated mine right after cleaning and it climbed to a reading of 47 before settling. It took about 24hrs.