[pct-l] Carrying extra water, which container(s) do you use?

[Anne Estoppey]

Hello everybody
 
I am planning to hike PCT in 2013. I am therefore in the process of collecting information about gear. I found numerous gear lists and I picked out some items already. 
 
There is one thing though I didnt find much information about. It is about carrying a large amount of water, while hiking in SoCal and in case the water springs are dry. 
 
I imagine carrying 1 gal of water is fine, in a platypus for instance. But how do you carry 2 gallons or maybe 2.5?
Can you have several platypus in your backpack without it to be 'slushing around'?
Do you carry extra water in other types of containers? Which ones?
 
I would be happy to hear about your experiences, good or bad!
 
Thanks a lot in advance :-)
Cheers
Anne