I am going to use different
containers for sure, try and cat proof them.
The 2 liters are superior because the bottles and caps are co2 resistant
and designed to contain pressurized gas. Juice bottles and caps are not
so there is an inherent risk involved with using them. Many people do
use them apparently without incident, but over time I think the chance
for failure of some kind is increased.
My 2 liter bottles are stored under the tank in the stand cabinet where
my 15lb cat likes to play. I put an adhesive hook strip of velcro
vertically on each bottle and the matching loop velcro strip on the
cabinet. The bottles are very secure and easily removed and replaced.