Hydrometer

[Guppy]

I just got a salinity refractometer and it read 1.028. My hydrometer reads 1.024. I assume the refractometer is correct. Would you have expected the hydrometer to be so far off? I even tried some rodi water on the refractometer to make sure it reads zero and it did.

 

[sublime-1]

Are you using a baseline ?


Hydrometer's are not really accurate, and most don't have the means to autocorrect for temperature.

IIRC, hydrometers are based on an accuracy rating of xxx/00ppm @ 76 deg.

Thus, if your temp is off, you will have off readings. Most GOOD refractometers do ATC (auto temp correction) whereby they'll adjust up or down depending on water temps.

The first thing I did when I got my refractometer is went to Neptunes and had bill check my Refractometer against his, with a sample of my water.

Turns out mine was .001 or so off.

Since I get alot of my livestock and rock there, and I use salinity equalization as one of my acclimation steps, I wanted it to be as close as possible.


Also, you can order Saline samples from the mail order house to calibrate your refractometer to a known.


BD

 

[v320]

Also, if you are planning to go to the next meeting, post a request on here, some people have a calibration solution that can be used to make certain your refractometer is reading accurately.

I’d definitely go with the refractometer over the hydrometer’s reading….