Not sure the dose, but add a teaspoon until you get 2 to 4 ppm of ammonia in your tank and when its gone in 24hrs you are ready.
for the future: depending on the size of your display tank, and type of filter, you could just keep extra bio media with your primary setup. I have a 90gallon tank with a sump that has a ton of bio-media. When I need to QT, I can just take ten gallons from that along with matrix rocks/bio balls/sponge foam from the sump and have an instant setup. Just put the aged media in the QT filter, refill the 90 and done. You could also throw your QT filter on your main tank until you need it, unless it would be an eye sore
92% of all statistics are made up on the spot.