Salt reading in New Tank

[Zinoq]

I just started a LR tank 55 gal. I had the Hydrometer at about 1.024 for LR. After adding about 45-50 pounds of LR(cured) the Hydrometer dropped to about 1.017. Why, Should I add Salt or will this correct by itself?

 

[kar93]

It could be the hydrometer, I recommend you get a refractometer.

 

[Randy Holmes-Farley]

Adding rock does not by itself alter salinity.

You can make a DIY solution to check the hydrometer here:

Reef Aquarium Salinity: Homemade Calibration Standards
http://reefkeeping.com/issues/2004-06/rhf/index.htm