does yeast, brown sugar and water really help c02??

i want a little more c02 for my girls will this yeast & brown sugar help??
if so how often do i change it

if not what will work (not to expensive or hard to come by)

never used brown sugar...

here is a link that helped me on my first grow....co2 mixture for 1 gallon jug ?

The chemical process will turn ur mixture to liquor.....Yeast eats the sugar and the process gives off CO2....I'd put a condom with whole poked in it over the bottle so the gas leaks out slowly overtime....The process will complete in 1-2 weeks depending on volume. Then when ur done...drink ur liquor...smoke some bud and do it again...

Wine making is legal BTW