Refractometer vs Hydrometer

tuggerlake26 · Oct 10, 2020

Which is better?

I've been using a refractometer for about a month now. I noticed today my mag and calcium were both high (1600 and 500), and this is without doing any dosing or water changes for a week.

I had a new Hydrometer sitting around, and decided to use it as I was curious if it would match my refractometer. My refractometer says 1.026, and this was also verified after using calibration fluid (purchased a month ago).

The hydrometer doesn't even stop- says the salinity is over 1.032.

Obviously I am concerned. Which one should I trust? I'm probably going to run to the store today to get new calibration fluid- maybe something is wrong with it?

Only thing that makes me wonder if the Hydrometer is right is my really high mag levels.

I'm using Red Sea (non coral) salt.

Any advice?

ScubaFish802 · Oct 10, 2020

I would say use a refractometer all day over a hydrometer. As long as you are keeping the refract. calibrated that should be giving much better / consistent results in my opinion.

hydrometer could have salt build up etc.. throwing it off

Ippyroy · Oct 10, 2020

tuggerlake26 said:
Which is better?

I've been using a refractometer for about a month now. I noticed today my mag and calcium were both high (1600 and 500), and this is without doing any dosing or water changes for a week.

I had a new Hydrometer sitting around, and decided to use it as I was curious if it would match my refractometer. My refractometer says 1.026, and this was also verified after using calibration fluid (purchased a month ago).

The hydrometer doesn't even stop- says the salinity is over 1.032.

Obviously I am concerned. Which one should I trust? I'm probably going to run to the store today to get new calibration fluid- maybe something is wrong with it?

Only thing that makes me wonder if the Hydrometer is right is my really high mag levels.

I'm using Red Sea (non coral) salt.

Any advice?

Have you left the calibration fluid out without the lid?