I just replaced my fill valve and all the other toilet components with a universal korky brand kit about 2 months ago and the fill valve is making a hissing sound once the water fills up in the tank. There are also air bubbles that come from the vents on top of the fill valve. I went to the Korky web site and they say that it is a faulty flapper but i checked to see if there is a leak by dropping one of those testers into the tank and there appears to be no leak. Any suggestions?
Those valves are notorious for hissing. If it's too loud, turn the service valve down to cut pressure. They are adjustable, so be sure the valve is not filling the tank too close to the overflow. Next time, just use food coloring to test. One or two drops in the tank will do.
