2016 Neptune Apex Salinity Probe Readings

[michaelr7170]

Hi,

I have the latest Apex model with an EB832 and a base unit, nothing else. I am wondering why there is so much fluctuation in my salinity readings, which is directly correlated to the tank temperature? The salinity readings rise and drop with my tank temperature all day long. I am also fighting an issue with the 832 tripping (with under 7A combined load, separate issue.....) and my temperature got down to 70 degrees last night due to this, and my salinity dropped substantially with the temperature.

I have a hard time understanding and trusting my salinity probe. I'm also measuring 1.25 on my refractometer while getting a 31ppt on my probe readings....

Any help is appreciated!

Mike

 

[Terence]

There are a few things going on here.

First, salinity readings are absolutely tied to temperature when derived from conductivity (how seawater is electrically measured). To adjust for this you can enable temperature compensation in the settings for that probe.

As far as accuracy is concerned, a properly located and calibrated conductivity probe will always be more accurate than the average hobby refractometer. Also, many in the hobby use salinity reference refractometers instead of seawater (not the same thing). Usually also those refractometer are not calibrated properly before the measurement. And, for instance, among other things Slight jolts to a refractometer like when it is laid on a hard surface, will throw it off. Even the light used as a backlight can change it.

Finally, your 31ppt is only about 5% off the refractometer value you have. Given many of the variables I would never expect multiple disparate salinity measurement methods like these to accurately match up with much any better than +/-3%. Finding consistency in that 33-35ppt range (as measured) has been the key thing for me.

As far as your load issue, be sure to contact our support team if you cannot work it out.

 

[michaelr7170]

Thank you for the reply and info provided.

So to clarify, how do I know what my salinity actually is with the probe? Is it only accurate when the temperature of my tank is the same as it was when I calibrated in the solution?

Could you please tell me how to enable temperature compensation?

 

[Terence]

Select the gear icon, then the probes icon (looks like a probe going in water), select your Cond probe from the list, click advanced, enter 2.2 in the temp compensation field, click the send to apex button in the upper right corner.

 

[Terence]

Oh, and follow the guidelines on our site for calibrating the temp probe. There are some nuances such as getting the solution temp near the same temp as the tank water by submersing it to equalize the temp when calibrating.

 

[michaelr7170]

Terence, I left the solution in the tank water for 20 minutes prior to calibrating when I installed a couple of months ago. I would do it again but don't have any solution unfortunately.

Is it ok to enable the temperature compensation now or do I need to wait until the temperature is where I want it to be? Ie currently it's heating up from the ev832 trip, at 72 degrees, but normally I maintain 77-78

 

[dragon99]

Mine seems to track correctly with temp. Salinity is definitely affected by temperature change.

 

[jonmos75]

Just make sure if you calibrated your probes without using temp compensation and then you choose to use temp compensation that you will need to re-calibrate the conductivity probe, make sure that you float the solution in the same location as the temp probe and enable Temp compensation and follow the calibration process.

 

[michaelr7170]

Just make sure if you calibrated your probes without using temp compensation and then you choose to use temp compensation that you will need to re-calibrate the conductivity probe, make sure that you float the solution in the same location as the temp probe and enable Temp compensation and follow the calibration process.

I know when I calibrated, I didn't use temperature compensation.... Unfortunately i don't have any solution left..

 

[PlanB]

I too have problems with my salinity probe. I followed the Apex startup (control freak newbie), and it didn't say anything about acclimating the calibration fluid. Unfortunately, I too don't have any calibration fluid left, so up a creek I guess.. :mad:

 

[MTWiley]

You can pick up more calibration solution for $2.95 at BRS which now has free shipping on all orders:

 

[michaelr7170]

You can pick up more calibration solution for $2.95 at BRS which now has free shipping on all orders:

I actually ordered some today shortly after reading these posts.. Unfortunately I'm in Canada so didn't get quite as good of a deal! Needed a few more supplies anyway so it's all good.

 

[michaelr7170]

So I re-calibrated again tonight, both my refractometer (using two different solutions of 1.026 fluid, both align) and my salinity probe.

After calibration my refractometer is showing a reading of 35 ppt in my aquarium.

My salinity probe is giving a reading of 32.6-33.0, which it was also giving before calibration as well.

SO - I want my salinity at 35ppt, should I trust my refractometer and assume my salinity is spot on?! Or should I assume my refractometer is reading high, and up my salinity until my probe reads 35.

 

[Bob Escher]

I'm trusting my refractometer and not my probe myself. I've read too many stories about probes not calibrating correctly ( not implying they don't at all just saying and mine didn't either both of them

 

[Addicted2ACRO's]

Hello, sorry I'm late to the party.
If your Salinity measures 1.024, 25 or 26 on a refractometer...what should the reading of your salinity be on your Apex display?
Mine displays 29.6, would you consider that to be accurate? If not, what should it read?
Thank you

 

[revhtree]

Just looking for a thread like this! How long does it take for temperature compensation to take effect as far as logging is concerned once you edit it?

 

[Leishman]

Just got my 1st Apex and the salinity calibration has ruined what I thought would be a fun weekend setting it up. Took several attempts to get to the second step, kept getting a fail on the 'acceptable range'. The two times I got to step two (after waiting twelve hours for the probe to dry) it would again fail on the, 'acceptable range', with a big red error box stating, "Calibration failed. Probe was not able to be calibrated".

Now what do I do?

 

[jonmos75]

You do not need to wait 12 hours for the probe to dry. When I pull my probe out of the water, and give it a good onetime shake to get off the large water out of the probe and will blow on the probe or use canned air to dry the probe in 30 seconds to a minute.

Instead of using the Automatic calibration choose the Advanced Tab and at the bottom of the page you will see Manual calibration. When looking at the Dry settling numbers you should see anything from 60-80, and when in the calibration solution you can see the settling number range from 200-800.

If the Dry settling numbers are in the 100's then you will need to reset the Salinity probe port back to factory settings, by manually calibrating the probe with NO PROBE connected to the base unit.

 

[Leishman]

You do not need to wait 12 hours for the probe to dry. When I pull my probe out of the water, and give it a good onetime shake to get off the large water out of the probe and will blow on the probe or use canned air to dry the probe in 30 seconds to a minute.

Instead of using the Automatic calibration choose the Advanced Tab and at the bottom of the page you will see Manual calibration. When looking at the Dry settling numbers you should see anything from 60-80, and when in the calibration solution you can see the settling number range from 200-800.

If the Dry settling numbers are in the 100's then you will need to reset the Salinity probe port back to factory settings, by manually calibrating the probe with NO PROBE connected to the base unit.

Will give it a try tonight. I hoping it's user error, not a faulty probe.

Thanks.

 

[Axel Juarez]

Are ya'll still there i need help So i am doing the calibration manually for the salt and it says 776 for the dry step and it wont go down what do i do ?