FIRST .... i have a SIX gallon heavily planted tank. ...
can i set it for 1 bpTWOseconds?
With the right needle valve, yes, you can easily achieve 1 bubble per two seconds.
Do note that your bubble rate does not correlate with the amount of CO2 that is actually dissolved into the water column.
if i buy a paintball tank (from some unknown source) where do i get it filled (some other unknown source?) . I'm in central western NJ
I would check out paintball stores for the purchase of cylinders/refills. Alternatively, some fire extinguisher places or home beer making stores will also refill cylinders.
You could also consider getting a larger (5, 10 or 20 pound) CO2 cylinder as well.
I would just go with a normal CGA320 regulator; that way, if you decide to upgrade to a normal (5 pound or up) CO2 cylinder, then you do not need to purchase a new regulator, etc.
Regulators with a CGA320 nipple can be easily adapted to paintball cylinders.
what if i go disposable?
This is an expensive alternative. The cartridges tend to run out quickly.