I'm not sure this whole DIY yeast thing is where I'm going to want to stay with my 72-gallon planted tank to be inhabited my Discus at a future point. I see an option to pick up (2) 20 ounce paintball tanks at a reasonable price. Will these be big enough to suit my needs? I am planning on constructing a Barr Venturi generator. I haven't even priced the regulator and accessories yet.