I gradually raised the tank temperature to 77 degrees and performed a 4G water change tonight.
As for my source of water, for most of the last month, I have been using:
a) large reverse osmosis mechanical filter by aquarium pharm. You connect it to a faucet and it pumps out supposively dechlorinated/pure water at a modest rate after 5-10 minute wait. I've taken this water and added a "stress coat dechlorinator" dose and waited an hour or two just to be safe. I believe it also said it handled "chloramine" but I'll have to check next time I am at the tank.
B) a stockpile of arrowhead mountain spring 5G tanks that we've had laying around here (we fell behind on using what was being sent out and I never got around to reducing the subscription). Stress coat dechlorinator was also applied to this water, just to be safe- but w/o a really long wait.
c) when I ran out of the arrowhead water and didn't feel like using the reverse osmosis, I would take tap water ....put it in an old arrowhead bottle, add dechlorinator, and wait 12-24hrs before using.
Would one of these sources be completely incorrect?
regarding nitrite levels, I wasn't checking on these until this week as I didn't have a clear understanding of what they were before
I have regularly tested ammonia, ever since the first fish died...which is how we got into the ammo-lock mess.