If bottle is below tank likely moving it forced back pressure/siphon of water from main tank. I would do a PWC
in case the mix is in the tank. Wait a few minutes after making the mix to screw on the lid, to allow mix to cool and start producing. Consider a saftey bottle between the canister and the tank to avoid the problem in the future.
1. There should be a pocket of gas in the bottle. Don't fill it up with water (I fill just past where the label would be in my mix, fwiw
2. You'll know you have CO2
when you see the diffuser going. After a new mix, I sometimes see some yeast floating at the top and bubbling fwiw
. This eventually goes away.