i tried to level out my sand to be equal in my saltwater tank but suddenly i noticed that my hydrometer arrow was not moving.(it usally moves up and down)

It is probably just stuck.... take it out and rinse it with fresh water!!!

They will all do that if you don't clean it in fresh water every time u use it, that why when i use man i will soak it in fresh water until i need it again.

I take it he must have one of those hydrometers with the suction cup that just stays in the tank.... They are not among my first choices in hydrometers for this very reason....

On another note....refractometers are very nice to have....I enjoy useing my refractometer... Easy maintenance and very accurate readings.....