I couldn't find a leak so left the gas on, lucky the pressure held. I didn't realize that the beer could absorb all of the head pressure if you don't leave it on.
I've been having some issues with my kegs leaking while the pressure is high to force carb. They've been slow leaks so what I've been doing is hitting them with a dose of about 30PSI and closing the valve so it can't drain my whole tank (again).
I assume there is a natural amount of pressure...
Recently I realized I was obsessed with beer but I wasn't doing enough about my habit (besides brewing and drinking). This has been a regular resource for me over the past couple years, so I figure I'd join and see if I can be of help back!
Britas (and many other water filteration systems) are a carbon and based filter. I can tell you what this does to water (which is most of what your beer is :)), and that is to remove off flavors from chlorine and it also has an effect similar to water softeners.
Again I can't know for sure...
I'm not a huge expert on things, but heres my experiences so far.
1) Carbonation depends on the type of beer. I believe that many beers are over-carbonated, to give a more crisp style (particularly the lighter lager of big name brands). My bottle conditioned beers tend to have about that level...