is hydrometer correct?

[Tang]

out of curiousity, I checked the salinity of my tap water and the hydrometer says it 1.003. Could that be correct or do i just have a bad hydrometer?

[allycat]

What kind of hydrometer is it? Mine floats in the water like a thermometer and is read by seeing how far it sinks along a gauge. Some must be calibrated.

Check it against a reading of an established tank?

[Tang]

its one that fills with water and the needle moves up to what the salinity is.. and my brackish tank is at 1.005 according to it, but it says my tap is 1.003

[Pufferpunk]

Best to calibrate those things with the same calibration solution as a refractometer or compare against a refractometer that has been calibrated with this solution.

[J-P]

have you tried the same thing with a bit of distilled water?

[Pufferpunk]

Distilled is the 2nd best way to calibrate.

[Tang]

im probably just gonna order a refractometer. I found one for $48, does this seem decent? http://www.fosterandsmithaquatics.com/p ... catid=9957

[Arny]

im probably just gonna order a refractometer. I found one for $48, does this seem decent? http://www.fosterandsmithaquatics.com/p ... catid=9957

I got this one and was told it's the best, looks same as the one your looking at, maybe just a different make
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... K:MEWNX:IT

[Pufferpunk]

Yep, way cheaper on Ebay. Just be sure to get the calibration solution too or it could be way off.