hydrometers to test cooler water

[rick12]

i have a coralife hydrometer and it works great for testing tank salinity at 79 f. what about hydrometers that test cool water.

 

[Randy Holmes-Farley]

Plastic swing arm hydrometers may often be inaccurate, but they are fairly good at correcting for temperature changes from about 68 to 81 deg F .

I discuss such issues here:

Specific Gravity Measurement
http://www.advancedaquarist.com/2002/1/chemistry

 

[rick12]

thanks

 

[Randy Holmes-Farley]

You're welcome.

Good luck.

 

[BangkokMatt]

It is better to just get a refractometer which isn't temperature dependent IMO

 

[BigAl2007]

I thought that unless the refractometer is "Temp Adjusted" it's just as inaccurate when out of it's temp range. That's why they have them with "ATC" (Automatic Temp Compensation).

 

[BangkokMatt]

<a href=showthread.php?s=&postid=11620347#post11620347 target=_blank>Originally posted</a> by BigAl2007
I thought that unless the refractometer is "Temp Adjusted" it's just as inaccurate when out of it's temp range. That's why they have them with "ATC" (Automatic Temp Compensation).

Thats what I was trying to say - Refractometers which are accurate and not dependent on surrounding and water tempererature. I didn't make it very clear.

 

[The_Browns]

When I test SG, I put water on and let the refractometer sit for about 30 seconds to let the temp adjust. I say ditch the hydrometer.