What should a normal salt reading be on a Apex Fusion?

[charlieborg]

I calibrated it to my hand held Refractometer.
And it was calibrated to distilled water.
I get 1.024 on it. so my question what should the apex read?

 

[sharis100]

APEX salt probe is the most unreliable piece of the Neptune APEX system. Count yourself lucky if it holds a decent reading for any period of time. Consistent readings are what you want rather than exact measurements. Unfortunately consistent salt probe reading have not been my experience- 2 APEX systems and 5 salt probes over 3 years....

 

[lmm1967]

I believe (from memory) that those show up by default as PPT.

1.024 is roughly 32 ppt. You can confirm. HERE

Be sure you have temperature adjustment enabled as well

 

[lshin037]

What @sharis100 said! 5 probes. WOW! My probe always goes to 37 a few days after calibration when it should be 35 (1.026). The only thing I use it for, and this actually came in handy one time, is a backup sensor to my ATO. My level sensor got stuck ON so it never activated the ATO. The only way I caught was because my salinity probe read 40.

 

[Steve Burton]

Also on your handheld refractometer, I would suggest calibrating to 1.026, You always want to calibrate as close as you can to the measurement you will be reading for accuracy.

 

[lmm1967]

And I agree with the others - those probes are just not reliable to be a whole lot of good. I certainly wouldn't expect more than a semi OK indicator of stability, although mine always drifted off to some random reading over a few weeks. Last I knew it was measuring conductivity in the landfill after I got mad and threw it in the trash.

Also on your handheld refractometer, I would suggest calibrating to 1.026, You always want to calibrate as close as you can to the measurement you will be reading for accuracy.

Some specifically want to be calibrated to zero with RO water - my red sea one is very specific about that in the instructions. I calibrate to 0 using RODI water - and them immediately use 1.026 calibration solution to confirm before trusting it. The challenge can be - do you trust your calibration fluid?

 

[ichthyoid]

I read on a R2R thread that temperature matters a lot with those probes. You have to enable temperature compensation (TC) and calibrate the temp probe also.

The Apex ‘salinity’ probe actually measures conductivity & converts that to salinity. In order to get an accurate reading, the temp variation is included in the Apex algorithm.

I haven’t set that up yet.

 

[Adam]

Can I get a have everyone's conductivity probes? I'll keep them as spares.

 

[lmm1967]

I think I have 1 or 2 GHL branded ones that are still wet - I'll keep them in a sump for you.

That is 1 thing the GHL seemed to do better than Apex - conductivity measurements remained stable and true as long as there were no bubbles in the sump.

 

[Adam]

The key to the Neptune is the TC and keeping the temp probe next to the conductivity probe. After calibration you can tweak the TC number without having to calibrate again. Then it's putting it in a bubble free area of the sump. It'll read within 0.5ppm after that.

 

[Shawn]

I also found that any power cables (skimmer, return pump, etc) near my salinity probe caused stupid numbers. Once I was able to move it away from other cables, I keep good readings. I run my salinity at 35 on the Fusion dashboard.

 

[lmm1967]

and to be fair - I have zero doubts that my challenges were 100% user error somewhere along the way.

 

[scuba steve]

Salinity probes in general are pretty hit or miss. I've had one that have never been accurate, one that have been accurate for years, and ones that have been accurate for years and suddenly wildly fail. They also seem to read drops in salinity quicker than gains. Drops are typically seen in real time or pretty close, for some reason rises take a few hours to catch up. After a water change I typically plan on 24 hours for the probe to get back to reading right. Never use them to control anything, only for alarms. And if it alarms look everything else over and verify before freaking out. I will say that they have alerted me to stuck ATOs before, that's what I trust them most to do.

 

[Adam]

I also found that any power cables (skimmer, return pump, etc) near my salinity probe caused stupid numbers. Once I was able to move it away from other cables, I keep good readings. I run my salinity at 35 on the Fusion dashboard.

Yes, I forgot about that part. In addition to the items you listed florescent light power cords really messed me up. I route all my probe wiring together, away from any power wires.

I found using pvc pipe is great for wire chases. Keeps everything organized.

 

[charlieborg]

Thanks for the advice! I did the calibration fluid on my handheld refractometer. Then checked it agenst my Ro water and it was on zero. Then checked my tank water and it read 1.024 ish. So I guess it is close. Now the Apex reads 49.2. Im going to try to get it where it needs to be and see if it holds.