Tank disaster overnight - Tiger barb dead, ich.. HELP!

oh, by the way. prime helps to keep ammonia and stuff like that less toxic to fish, but it won't help the test reading, might even make it worse.
 
I've continued with night and day water changes about 25% of the tank. The fish look fine with no more white spots. All fish are eating vigorously and swimming like crazy. My cory catfish is wiggling all over the tank as well as my tiger barbs are zipping through the tank. However, I only have 5 left seems like 1 is always left behind hiding behind plants or a rock. The GBR looks more blue due to the high temps recently set at 86Deg. Tonight I continued with salt but stopped prime and used Stress Coat bc the prime has made my tank smell really bad. I came home and all i smelled was an awful aroma coming out of my tank.

Currently my ammonia has not dropped still steady at .5 (light green) everything else looks solid at 0 nitrite and 5 nitrates. 6.8 PH and I plan on slowly lowering the temp to 82 deg since the fish tank was feeling very hot at 86.
 
Prime wont make your tank stink when dosed properly. Disturbing an unproperly maintained gravel bed will.
 
AquariaCentral.com