I have checked out CO2 before. No real access for me to reasonable size tanks. Beer making? I think they were like 6lb. tanks or something odd. You need much more. Much, much more in your case specifically. Just a maintenance thing and you will need 2 20lb. tanks minimum, the 2nd so you can change out and re-fill etc.. With trying to lower your alk I would think these little jobs are just too small a tank, at least from I have read. OBTW, I live in Jersey. If I can't get large scale containers of compressed gas, toxic liquids or solids or other major corrosives and the like, I would think no one else can, because we manufacture so darn much of it right here in the garden state. Just my .02 anyway.