i bought the JBL Profi 2 set with a night switch-ff solenoid valve and the german lady gave me a second co2 bottle (500gr) for free, all for 220 Euro.
it should be here in a couple of days.
as for local petshops, yes, there are a few around. but cause of the small market, they import the same stuff. so if you visit a couple of these shops, you've seen them all
as for prices,well, let's not get into that.
ebay is my source for all my needs.
as for the water's hardness, depends on your area. where i live, it's hard water.
will post a my comments on the JBL set when i install it