questionable c02 aquarium system (any comments appreciated)

hey guys i was reaserching a c02 setup for a hydro system and came apon this:
http://www.dupla.com.au/pages/co2.htm (3rd product on page)
only $10 a refill and its supose to last a month for up to 150 liter aquariums...

would this be a good alternative to the yeast suger and water 2 liters everyone has been using? (with only last a little over a week)

could u just attach air tubes from a 2 liter setup to a box with your air pumps in it for a nice homemade kit?

seems like a great idea to me and doesnt involve and big heavy c02 canisters.

if u have any comments good or bad please post i dont care i just wanna know what people think!!

edit: forgot to add that the 4th thing on that page would help also, it s an adjustable c02 meter...

 

well first of all there 20oz i have like 4 of them (i play paintball)

you would also need a regulator... coiled remotes that arnt ment to regulate airflow, u could by only opening the valve a little but it isnt accurate at all (every time you put a new tank on the pressure would change slightly)

but i reaserched a bit more today anyway and found this...

seems to me like it would be perfect, its got the psi output also. all i would have to do is run a tube from the output into a box with my airpumps only problem is its $80 before shipping...

so if anyone can find a cheaper adjustable valve with a 1/2 NPS tap input it would be a huge help to everyone at grasscity.
just think all u would have to do is pay $3 every few weeks and have perfect ppm c02 bubbler hydro systems