DIY CO2 system question

I have been running my first DIY Yeast CO2 system. I of course did
everything not quite the way discribed:

I used a one gallon plastic milk jug. Filled it half full and put in extra
sugar (about 3 cups). added 1/8 teaspoon baking soda and 1/8 Teaspoon yeast
(standard red what ever it was). I put a diffuser in the tank (Bell type -
plastic pop bottle with the sides cut out.)

It has been running for three weeks and is still going strong. the bell
never empties and it occasionally releases excess CO2.

So now the question: I know that the yesat solution will get Alcohol in it
before it dies. Since I used a large container, can the alcohol get into the
tank to posion (inhibriate) my fishies? How much of a problem should I watch
for?

I have 25 gal tank with 14 small (1 inch mostly) fish. 4 plants around the
difusser. pH is 6.6, Kh around 5. 0 nitrates, nitrites, ammonia. I do weekly
water changes of 20%.

The fish are a bit agitated this morning. Normally, they get along better.

Thank you,

Ken