Deep Six Hydrometer
 

On first use it says to fill and let it sit for 24 hours. Should this be with fresh water or salt water?

I believe the Deep Six is a float arm and is temp corrected like the Seatest. I think they just want you to clean it. My guess is FW. SW coats the inside, and this is why you rinse it after use. It is probably also so you can assure a zero reading for FW.

If you can, get a refractometer, or occasionally get your SG checked by another reefer in your area.

This is a good thread on temp correction for some of those floater things....(those are calibrated for 75 degrees F)
here

Lets hope so.. I quickly tried it in my tank.. it said my SG was above 1.030 :question: . I really hope it was just because it has to sit in that RO water... Lets wait and see I guess..

Chad