If it's just a 5 gal
tank for a Betta you could get away with dosing to 2 PPM
of ammonia instead of 3-4. Here's a calculator to help measure: Calculator
So if your ammonia is 10% ammonium hydroxide and you want to dose to 2 ppm
of ammonia, according to the calculator you'd need to dose 0.38 ML of ammonia. You won't need much. You could also just add a few drops, let it circulate for a half hour, test the water with your ammonia kit and see where it is on the test. If it's below 2, add a few more drops, let it circulate, test, etc. and repeat until you get to 2 ppm
of ammonia on the API Kit chart.