No Co2 diffuser
 

I have a DIY Co2 generator but I have not made a diffuser yet, if I stuck the tubing into the water stream that my filter makes will it still work or do you have to use a diffuser?

Some people use a mini power-head to feed the CO2 into and the powerhead chops it up and distributes it throughout the tank. If you do it in this manner, instead of just letting the water flow take it, you'll get a better effect from the CO2.

Alternatively, you could feed it through your filter, although be aware that depending on the type of filter you have it could either cause an airlock every so often or the CO2 could have a negative effect on the filter seals (ie some people have reported that it could harden them up).

With a yeast based mix you might not get the pressure up for a standard diffuser to work, so an alternative method may be better.

The powerhead method seems to be the easiest to do, but powerheads cost around $20. I got my CO2 diffuser off of E-Bay and it works great! Just type in CO2 Diffuser on E-Bay and get the Nano one. That seemed to work the best for me :) But there are also models for 55 and 75 gallons :)