i was cleaning out my salt water tank and its that time of week that i had to do a water change. i cant get to any store that sells a hydrometer because the only one is like 50 miles away and i cant get out there untill the weekend. My dog ran through the living room and nocked over a tripod that i had set up so i can film my tank to put it on a TV show and the tripod hit the table and the hydrmeter that i was about to use fell and the dog crushed it(it was glass) My tank is half empty and i need a quick fix that will let me fill the tank back up quickly and accurately with the right amount of salt and not a 1/4 salt to water ratio because that doesnt work. i need to do it quick because i have a yellow tang that is about to go in shock and they are very quick to die so i need something soon what do i do?!?!?