OK, you're being too "wimpy" on your water change percentages. I'm not sure what's causing you to hesitate but if it takes 75% changes to get you down in the "under 0.25ppm" area and keep you there for a while so you can go out and have a life, then that's what you need to do. Don't worry about the bacteria, they will get enough ammonia to survive and when the filter isn't cycled, the fish need to be protected from the ammonia and nitrite getting above 0.25ppm, which is something that will hurt them much more than any water changes or pH variability.
Later on, once your filter is cycled again, you may be a candidate for a small amount of crushed coral in your filter, we'll have to see. We don't like to jump in to that too fast and its nice to have lots of different members look the situation over in case I or any of the others make a mistake or miss things.
~~waterdrop~~