Salty&Onion
Fish Aficionado
Welcome back Colin!just wash the tank out with warm soapy water a couple of times and then rinse well. that will get rid of any worm eggs and most parasites 9assuming there is any).
or you can use straight household bleach. slosh it around the tank, wait 5 minutes then rinse out well.
white vinegar can be left in contact with silicon for hours and won't affect it, but will kill most things.
70% alcohol will kill everything too and you can wipe a heap of alcohol on the inside of the tank. leave it to dry then wash with soapy water and rinse well.
When you were away I have been you