So I recently picked up an Apex and of course started measuring conductivity with it, which is super cool. Problem is, I get completely different readings between a specific gravity swing style device (1.025), my new refractometer from BRS (1.30) and the Apex (around 32.3). Soooo confused about which to trust. I have calibrated the BRS device with RO water. But I can't imagine the tank is really at 1.30 since all the critters seem happy. Thanks...
Salinity help: Apex, Refractometer, specific gravity
- Thread starter Particle
- Start date
- Tagged users None
Brad Miller
Valuable Member
Most Apex sensors that I know of, come with a calibration fluid for you to calibrate that sensor before using it.
You mentioned Apex conductivity, then salinity for the BRS ??
You mentioned Apex conductivity, then salinity for the BRS ??
BoSalman
Active Member
Try and calibrate your refractometer with a 35ppt solution, and check that against the apex probe.
Since you're calibrating apex with their supplied calibration liquid, it does make sense to calibrate the refractometer with a 35ppt liquid as well (instead of RO water).
I wouldn't use a swing type hydro..
Since you're calibrating apex with their supplied calibration liquid, it does make sense to calibrate the refractometer with a 35ppt liquid as well (instead of RO water).
I wouldn't use a swing type hydro..
Randy Holmes-Farley
Reef Chemist
Staff member
Super Moderator
Excellence Award
Expert Contributor
Article Contributor
R2R Research
My Tank Thread
Many people find issues with APEX salinity, for reasons I am not certain of. Might be temperature calibration, which is critical. THe APEX must know the calibration solution temp.
The swing style is completely un-trustworthy. The refractometer, assuming correct calibration, is probably the most accurate. As for the apex, my advice is as follows:
1) If you are using the salinity probe on the base unit, put it and the temp probe very close together.
2) Micro bubbles makes probe sad! Keep it far away from your skimmer.
3) Go into the probe configuration, and turn ON temperature compensation. The apex ships with this off by default.
4) Toss the *unopened* neptune salinity calibration packet in the sump for an hour or so to let it equalize temp.
5) Rinse the probe off in RO/DI, dry it off, make sure to stick some toilet paper up in the probe end to get all the water out. Let it sit dry for about 10 minutes.
6) Follow the calibration instructions now.
1) If you are using the salinity probe on the base unit, put it and the temp probe very close together.
2) Micro bubbles makes probe sad! Keep it far away from your skimmer.
3) Go into the probe configuration, and turn ON temperature compensation. The apex ships with this off by default.
4) Toss the *unopened* neptune salinity calibration packet in the sump for an hour or so to let it equalize temp.
5) Rinse the probe off in RO/DI, dry it off, make sure to stick some toilet paper up in the probe end to get all the water out. Let it sit dry for about 10 minutes.
6) Follow the calibration instructions now.
SPR1968
No, it wasn’t expensive dear....
Reef Squad
Reef Squad Leader
Excellence Award
Reef Tank 365
UK Reef Club Member
Hospitality Award
There are lots of threads on issues with the salinity probe calibration and whenever I use the solution the Apex does not match my refractometer which Ive trusted and in the basis everything is alive, I’m happy with it.
I’ve also found it needs cleaning every 3 months otherwise you’ll get wild readings
What I do is wait until the tank matches 35ppm on my Refractometer, then do a manual calibration but we’re it tells you to put it in the solution it goes back in the tank water
I haven’t had any issues since doing this and Apex matches my refractometer
I’ve also found it needs cleaning every 3 months otherwise you’ll get wild readings
What I do is wait until the tank matches 35ppm on my Refractometer, then do a manual calibration but we’re it tells you to put it in the solution it goes back in the tank water
I haven’t had any issues since doing this and Apex matches my refractometer
