The reason you had nh3 issues is because the QT tank/filter wasn't cycled properly. I use a Magnum 350 Pro with two biowheels spinning on my main tank at all times so I can easily transfer one to my QT tank for instant bio-filtraion.
IMO Biowheels are the easiest most effective filter to use on a QT. Like all filters they need time to build up bacteria. Just putting the wheel in the sump for a month will work for the most part but running the filter with the wheel is much more effective due to it being exposed to air/water.
New fish are already stressed from being captured, transferred, & keep in sub-standard conditions. Why add to it with trying to quickly acclimate them to a sg/ph change that can be as much as 0.006 in sg and .5 in ph.
Keeping the qt tank sg the same as the main can be too stressful for newly acquired fish/inverts unless you keep your main at 1.019-1.022 sg which is where most fish stores/online places keep their sg at.
If you keep your main closer to 1.025 sg then even
drip acclimating for 2 hours can be stressful and can possibly cause osmotic shock in fish/inverts with the rapid change in sg/ph leading to sickness or death depending on the change in sg/ph that the fish was kept in.
Personally I keep my qt tank at the same level as the lfs (ph 8.0 sg 1.019) and slowly raise the sg/ph to the main sg/ph of 1.025/8.3 over the course of 3+ weeks per
first &
second articles in advancedaquarist.com.
The use of a
refractometer is highly recommended while performing any sg changes whether if it's matching lfs sg level or main sg level to the qt tank. Adjusting the sg down is less stressful to fish coming from that environment and slowly raising it a little bit every other day gives them time to adjust.