gee idk lisa im quickly running outta ideas. Seems like you're doing everything right so far. You said there was a possibility of copper pipes? When you filled for water changes, did you run the faucet for a minute or so to flush out the copper?
That I didn't do -- is running for a few minutes long enough to do that? The house was built in the 60's and hasn't had any plumbing upgrades -- I have no idea when they started using copper pipes and when they stopped.
It's all crazy isn't it? I guess this is why I'm more frustrated because I really can't figure out what needs to be fixed. Besides copper, any idea what else inverts might be sensitive too?