So I just did a very large change, about 75%. I just stuck the gravel vac in and sucked water out. No sand was disturbed. I did rinse the filter media but plugged it back in as soon as I was done. After reading your post I just unplugged it. However, it's still very cloudy. I moved Dumbledore to a 1 gallon for now. I took a picture of the tank after this last change.
The only thing I can think of is when I kicked up a lot of sand, one of the root tabs was disturbed too. I use the API Root Tabs and API Leaf Zone for fertilizer. I did poke around in the sand with a tooth pick to release gas but I'm still not sure what to do.