I cant find the elite filter at my LFS. so i cant use this method.
It doesn't need to be the Elite filter. Any very small internal filter - powerhead with a plastic filter chamber attached on the inlet - will work just as well. Bigger ones also work, but are more of a visual problem in the tank. I use one made from a spare filter I had laying around, which isn't even sold anymore. See DIY CO2 System - How to do it