Salinity has been off???

[Randy Holmes-Farley Verified Community Expert]

I'm not sure which is off, but just a note: the Sybon does not appear to be a true seawater refractometer, So be sure to not rely on calibration of it with RO/DI or it will likely be off.

You can make your own standards for both devices here. You can also cross check them in each others solutions:

Reef Aquarium Salinity: Homemade Calibration Standards by Randy Holmes-Farley - Reefkeeping.com

 

[Nick Rose]

I'm not sure which is off, but just a note: the Sybon does not appear to be a true seawater refractometer, So be sure to not rely on calibration of it with RO/DI or it will likely be off.

You can make your own standards for both devices here. You can also cross check them in each others solutions:

Reef Aquarium Salinity: Homemade Calibration Standards by Randy Holmes-Farley - Reefkeeping.com

So I made the conductivity standard I think from the results, I did not weigh out the water and salt accurately enough but i guess close enough. I did order the Pinpoint Salinity monitor (comes tomorrow 7/13) and redsea refractometer (probably end of this week or next week). When I get those devices I will post those results.

Here is the results:
Hanna Checker - Calibrated to Hanna Packet at tank temp.
-Hanna Packet - 35ppt
- DIY Standard - 33.8ppt
- Tank - 32.3ppt

Opticon Refractometer - Calibrated to Continuum and Brightwell Standard
- Continuum and Brightwell - 35ppt
- Hanna Packet - 1.020(26.6ppt) I know Hanna Packet is not for the refrac. but still wanted to test it.
- DIY - 33ppt
-Tank - 35ppt

 

[Reef.]

I recommend the Tropic Marin high precision hydrometer. Unless you’re prone to break delicate equipment.

I use the hydrometer to check and calibrate the refractometer every week or two.

This...it will solve your issues straight away, just buy a 500ml measuring cylinder to go with it.

 

[Nick Rose]

This...it will solve your issues straight away, just buy a 500ml measuring cylinder to go with it.

I did buy that and it closely matches the refractometer.

 

[Reef.]

I did buy that and it closely matches the refractometer.

Problem solved, you now have something that doesn't need calibration to check your other equipment.

 

[Salted]

I guess I could always buy the Tropic Marin high precision hydrometer and see where that reads to tell me which one is correct or closer.

I'm an outlier here. I use a simple Instant Ocean swingarm hydrometer (my son does also) and have been for a year and a half now. Blasphemy I know, but guess what? Both consistently match my Tropic Marin high precision hydrometer. Every other month I float the TM and check the IO swingarms. No way I'm messing with refractors and calibration as I'm nearing the limit of what this hobby requires timewise. Bring on the hate and pitchforks.

 

[Nick Rose]

@Randy Holmes-Farley

Just got the pinpoint meter. Here is the previous results and the pinpoint results.

Here is the results:
Hanna Checker - Calibrated to Hanna Packet at tank temp.
-Hanna Packet - 35ppt
- DIY Standard - 33.8ppt
- Tank - 32.3ppt

Opticon Refractometer - Calibrated to Continuum and Brightwell Standard
- Continuum and Brightwell - 35ppt
- Hanna Packet - 1.020(26.6ppt) I know Hanna Packet is not for the refrac. but still wanted to test it.
- DIY - 33ppt
-Tank - 35ppt

Pinpoint meter - Calibrated to Pinpoint Standard
- Pinpoint Standard - 53mS (34.95ppt)
- DIY - 52.5mS (34.5ppt) (Tested the Hanna at same time, 33.8ppt)
- Tank - 50mS (32.7ppt) (Testes the Hanna at same time, 32)

 

[Randy Holmes-Farley Verified Community Expert]

The Hanna and Opticon only claim +/- 1 ppm accuracy.
Pinpoint may be similar, though I've not seen specs.

My best guess is the tank is low, like 33 ppt.