Totally get why the care guides drive people crazy sometimes. My buddy across town has to filter everything for his plants, but my neighborhood's pipes must be older or something because straight from the tap works fine here too. It's wild how much the local water can change from one block to the next. Makes you wonder if the people writing the guides ever test different city systems. What's your water hardness like, out of curiosity?
Always followed that filtered water rule to the letter and mine still got brown tips. Switched to plain tap water left out overnight last fall as a test... three new leaves popped up in weeks. Guess the guides don't know what my local water is actually like. You just saved me a lot of hassle.
Yeah that overnight tap water trick works great until summer hits. They pump way more chlorine into the system when it gets hot, so your fall fix might turn on you by July.