Well, the reason we like to use pure household ammonia is for control. It means you know much more accurately how much ammonia you are dosing. Other methods not only do not allow as much control over dose, they also give much less control over time (time at which dosing occurs.) Also, the term "pure ammonia" sometimes imparts incorrect meaning to some people. What we use is a very dilute (most common is 9.5% ammonia dissolved in 90.5% pure water) solution that is frequently sold in the "mop and broom" sections of household or hardware stores and is meant as a "generic" cleaner of less cost than typical floor cleaners.
Are you in Aus./New Zea.? We do sometimes have trouble directing newcomers to sources for this ammonia down there.
~~waterdrop~~