Digital Aquatics Salinity Probe Issue

n2585722 · Jun 25, 2017

If I do a two point on a temp probe I use ice water for the low point and the tank water as the high point. You will need a reference thermometer to do this. Or at least one you trust. Use the reference thermometer readings in each as the setpoint.

crs751 · Jun 25, 2017

Ok thanks. Do you need to calibrate them or are they good out of the box?

n2585722 · Jun 25, 2017

They are usually close enough out of the box. Temp is not that critical until you get close to the extremes. If you have several probes in tue same tank you can get them to read a lot closer to each other by the 2 point calibration.

crs751 · Jun 25, 2017

Thanks. With regard to the salinity probe, FYI it read 35 in the 35 calibration solution so we'll see what 24 hours brings. I did purchase a new salinity probe as I'm sure this one is over a year old.

crs751 · Jun 27, 2017

Got my new salinity probe today and just finished calibrating it. In air the raw data number was -1981 and in the calibration solution it was -965. However, when I copied the raw data number from the calibration fluid into the 35ppt box it changed the 0 box to -965 from the original copied raw data number of -1981. When I put the probe in the tank it reads 35ppt which I confirmed with the refractometer. However, given my previous issues I am a little skeptical of the results and why the raw numbers changed. Is the module the problem?

I also got a 1/2" John Guest fitting to insert the probe and intend to set this up soon. I tried a dry fit and the probe fit is a little sloppy. What do you guys use to make a better seal? Teflon tape or silicone caulk or something else?

Thanks.

elmexotics · Jun 27, 2017

crs751 said:
Got my new salinity probe today and just finished calibrating it. In air the raw data number was -1981 and in the calibration solution it was -965. However, when I copied the raw data number from the calibration fluid into the 35ppt box it changed the 0 box to -965 from the original copied raw data number of -1981. When I put the probe in the tank it reads 35ppt which I confirmed with the refractometer. However, given my previous issues I am a little skeptical of the results and why the raw numbers changed. Is the module the problem?

I also got a 1/2" John Guest fitting to insert the probe and intend to set this up soon. I tried a dry fit and the probe fit is a little sloppy. What do you guys use to make a better seal? Teflon tape or silicone caulk or something else?

Thanks.

Can you please give us a call tomorrow so we can help you with this. 425-527-0995. Or email us support@digitalaquatics. Please include REEF2REEF in your email and a phone number so we can call you

n2585722 · Jun 27, 2017

The John Guest fittings have an o-ring as a seal, so it might feel a little loose. Mine seals fine with the fitting.

crs751 · Jun 27, 2017

Ok thanks I'll call tomorrow.

elmexotics · Jun 28, 2017

crs751 said:
Thanks for the reply. I'll check the module but I think it has the latest firmware. BTW how do you calibrate a temp probe. What temp value do you use?

Can you please contact us at support. I would like to walk through this with you and it will be much easier on the phone than through a forum.

pickupman66 · Jun 28, 2017

@crs751 a Refractometer and a Salinity conductive meter will read differently when using the same solution.
http://reefkeeping.com/issues/2004-06/rhf/index.php

IN summary:
For Refractometer:
This 3.65 weight percent sodium chloride solution can be made by dissolving 3.65 grams of sodium chloride in 96.35 grams (mL) of purified freshwater. I think I scaled this up in a thread here on R2R. (https://www.reef2reef.com/threads/diy-salinity-calibration-solutions.220052/) Per RHF, exactly 3.65 grams of salt and 96.35 mL of fresh water. I did math: 1tsp per 163.66 ml of water

For conductivity:
To make a 3.29 weight percent sodium chloride solution, dissolve 1 teaspoon (6.20 grams) of Morton's Iodized Salt in 182 mL (182 g) of freshwater (making a total volume of about 184 mL after dissolution of the salt). This solution can be scaled up as desired.

FWIW, i have never used the command lines. Mine has stuck, but you need to use a PC to do it because hat page will refresh. I always write down my raw data and if I hit calibrate and it jumps a bit, I will tweak it just a hair and calibrate again.

as for Temperature, that is hard. If you can get a hold of a good digital thermometer that you feel is accurate, then just calibrate to that.

crs751 · Jun 28, 2017

Thanks. I did calibrate the probe with solution specifically used for probes. When I checked the tank water with the refractometer it read 35ppt which is correct. The old probe was off. The new probe apparently locked up. I need to call customer support to work out any issues.

crs751 · Sep 14, 2017

Update on my probe issues. I received the SL2 module back from DA and all is connected and working properly. I tried to use a push connection fitting on a reactor line to attach the probe but even though the 1/2" push connector held the probe it leaked like a sieve. Any insight on what you guys did to keep it from leaking around the probe?

n2585722 · Sep 14, 2017

It worked for me. Also Avast marine sells something they call probe holders that I bought several of. I use them for my float switches. https://www.avastmarine.com/collections/replacement-parts/products/kalk-stirrer-replacement-parts-1 Item 16 on the list.

crs751 · Sep 14, 2017

Yeah it holds the probe to the point that you need to push on the retainer to release it but doesn' the seal enough to keep it from leaking.

n2585722 · Sep 14, 2017

It has an o-ring in it that seals around the tubing. If it is 1/2" then it should work unless something is in there that is breaking the o-ring seal or it might have a bad o-ring.

EuroDriver · Sep 21, 2017

FWIW, I had issues with several salinity probes some time back. I was about to ditch the SL2 along with the entire RKE controller. I finally figured it out when I had just bought a probe and it lost calibration in a very short period of time. I sent it back to DA and they replaced it, reporting that there was a leak at an O-ring.

Since then, I make sure that the top portion of the probe is well above the water line (I make sure that no more than 1/2 the probe is submerged) and I haven't has a similar issue since. (Issue-free for around the past 3 years or so).

Hope this helps someone.

crs751 · Sep 21, 2017

Good to know. Thanks for the info

Bmezz · May 23, 2018

So i have been using the salinity probe SL2V2 for a few months and readings have been fairly accurate then all of a sudden readings went down to 5 and 6..just nuts.. So i calibrated last night and all was good for about an hour 34, 35.. then the reading started going up.. 60, 90, 120.. I think when i left this morning it was 300!
Is the probe shot or what do you all think? not that old of a probe.. any ideas??