Seems to me you have burned all your inhabitants in your tank as probably as the limewater had not dispersed enough before you added it. Dangerous stuff!! Using it is only effective if the Ph is below 8.2. I know it is a bit late now, but why not do the easy thing and do a weekly water change to keep calcium levels steady instead of messing about with chemicals. In a fully dissolved solution(kalkwasser) the PH is 12.4. Scary! Try to keep things easy and straightforward.