3 different methods, 3 different salinities???

[daftwazzock]

I got a hydrometer saying I have a salinity of 26, a refractometer saying its just under 30, and the probe on my apex says its 33.5..

what the heck is going on? Which one is right? Temperature is 26 C

I guess the refractometer is the correct one here?

 

[Super Fly]

depends whether hydrometer is new (used ones should be cleaned/rinsed after each use and sitting with clean water in it or else can give false reading). Also was refractometer calibrated? Refractometer's body temp also affects reading, so I always keep mine in the 1F vs basement where tank is.

If you have calibration fluid, I'd test all 3 to determine which one is providing incorrect #.

 

[BloopFish]

You should calibrate the refractometer with 35ppt calibration fluid, if you don't have that on hand calibrating with RODI or distilled water is better than nothing. However, without using a 35ppt calibration fluid it is hard to say if its accurate at all.

 

[daftwazzock]

I just calibrated the refractometer with RODI water. Now its reading is matching the hydrometer on both the batch of saltwater I mixed and the tank. So my apex probe is the one giving a wildly inaccurate reading it seems. Cool to know that I've been running a tank that's been way way under salinity for a few months now. Surprised my LPS haven't all died (my SPS frags did)

Honestly I've been relying soley on my apex for salinity ratings and calibrated the probe per their instructions. It's at least 10 points off. This is absolutely insane.

 

[Super Fly]

I would highly recommend getting a calibration fluid and using it often on the refractometer as they get out of calibration often. ALso heard some folks getting different reading from elec sensors vs manual... I keep both a regular thermometer and elec thermometer in tank, elec thermometer always reads 1-2 degrees higher.

 

[daftwazzock]

I would highly recommend getting a calibration fluid and using it often on the refractometer as they get out of calibration often. ALso heard some folks getting different reading from elec sensors vs manual... I keep both a regular thermometer and elec thermometer in tank, elec thermometer always reads 1-2 degrees higher.

I guess this is the stage of me in being in the hobby where I learn about the importance of keeping your probes calibrated

 

[Super Fly]

Yes, we live and learn esp in this hobby