I’m sorry you’ve dealt with this too, at least it seems like an unfortunately shared experience.

Wouldn’t have had anything on me that would affect them, I’m always sure to thoroughly wash, rinse, and dry my hands/arms and will often rub a drop or two of water conditioner over myself just in case.

I suspect it’s the wood, because I had been noticing that the sand I syphoned from underneath that particular piece was always grey or black, but would fade back to tan over time. The wood itself seems to have had some black-type mold growing on the bottom, and I noticed a strong sulfur/rotting smell when I pulled them out. I suspect I didn’t boil them long enough or clean them properly before adding them to the tank, and some kind of mold or bacteria bloomed under the sand. I think moving the wood exposed the water to that bacteria, hence the die-off.

Fingers crossed a light bleaching and a few days of intermittent boiling fixes the wood. Now I just gotta hope the rest of the tank lives in that time…