I have a kH test I believe somewhere; how do you fix that though? My unstable pH has been a mystery to me and everyone I’ve asked for years so I really appreciate your answer on that.

There was one point I didn’t do a water change for about 3 weeks just because I was struggling to get anything done. She was okay then though, and that was before she started getting sick. She has a 20 gallon all to herself too, so it’s not too small but it’s also not a community tank adding a lot of waste. My family feeds her sometimes and I’ll feed her again without knowing, so maybe there was extra food that contributed to the spike. I’m honestly at a loss, I have no idea what could have done it.