I want to do C02! I need something easy enough for idiots

[Wayne Dwops]

Ha! I've read the primer to DIY CO2 and my dad can build it in a jiff but I really don't understand, at all, how the system works and I need something cheap and safe for my shrimp. Since my tank is only 20gallons and I am a complete idiot I'm thinking of just getting this:

http://www.amazon.com/Hagen-Nutrafin...rds=co2+system

and this ceramic diffuser

http://www.amazon.com/Fluval-Ceramic..._petsupplies_3

Is this system invertebrate safe though? How do I measure how much CO2 is in the tank to make sure my shrimp are not getting gassed? Is that what a bubble counter is for?

Also, will I need to use something to keep my PH and/or GH high enough for my RCS?

And, is there anything else I need to buy for the sugar/yeast method kit?

thanks.