I JUST BOUGHT A PLANT DIFFUSER

I JUST BOUGHT A USED NUTRAFIN PLANT DIFFUSER AND I DONT WANT TO BUY THE REFILL PACKETS I HEARD THAT THERE IS A CHEAPER WAY OF MAKING YOUR OWN ACTIVATOR POWDER DOES ANYONE KNOW??

here is an article and here's the basic recipe...
"A SOURCE FOR CO2
The third step is to create CO2. I mix 3/4 cup sugar, 6 cups water and a pinch of yeast (roughly 1 teaspoon does the trick). The exact ratio of ingredients is not critical. For example, I use enough water to fill the bottle to about 3 inches from the top. You don't want to get the mixture too full, as the mixture may foam a bit, and you don't want the foam flowing into your tank.
Using the above mixture, I regularly get 10-14 days of strong CO2 production, at a rate of one bubble every 3-7 seconds. When the system stops bubbling (the drop in gas production is often precipitous), dump out everything and mix up a new concoction. "


http://www.thekrib.com/Plants/CO2/co2-narten.html

here's another
http://www.plantedtank.net/articles/DIY-Yeast-CO2/7/

and another (different) recipe
http://www.aquaticplantcentral.com/forumapc/diy-aquarium-projects/14453-diy-co2-guide-pictures-recipes.html

and a link with more links
http://www.plantedtank.net/forums/planted-tank-faq/23742-comprehensive-diy-c02-index-recipes-reactors.html

Same concept as brewing shine. well at least the first step. Shine is a little more involved.