angry

Alright so I just bought a powerhead for my 5 gallon bucket to mix the salt and water. Works good. Even though the powerhead is meant for a 40 to 60 gallon tank. But the bucket does not splash. I had it sitting over if he using an airstone. And what's bugging me is. This instant ocean hydrometer I have. I checked it 5 times in a role by watching how to use these right. And I get a different reading everytime. I don't know what it is and it's bugging me bad. Can anyone tell me the right way to use it?