Hello!
I've finally bought myself a CO2 bottle / regulator..... and I need to have
it filled up.
A shopkeeper told me I have to put the bottle into the freezer first....can
you please verify this? and give me more detailed instructions on doing
this?

The bottle is 1,5 liters.........how long do you reckon that would last for
a 180 liter aquarium with 60% plant coverage?

Thanks =D