How to read floating thermometer/salinity gauge?

[reefburnaby]

SoS,

I guess you got one of those hydrometers that float in your tank. Hmm, I have used one of those and I usually read it from below the water. The delta between the line above the water and the line below the water should be relatively fixed. You can take the measurement from above the water and subtract the difference to get the real reading.

Oh...those things are fairly accurate but they break really easily.

- Victor.