The taste could be improved quite a bit actually by using apple cider, honey and champagne yeast! You would actually be making a meade ( I think that is the correct spelling). I made a few batches back in my homebrewing days
For those who are so inclined, and of legal age...take one gallon of non-pastuerized, preservative free apple cider (not apple juice) and boil it for 10-20 minutes. Add 1 pound of non-pastuerized, preservative free honey (flavor of your choice) and boil for a couple more minutes. This sterilizes the cider and honey and kills off any wild strains of bacteria/yeast. Cover tightly and cool to the recommended temperature for the strain of champagne yeast you are using. Make sure to use champagne yeast as ale/wine yeast won't survive the higher alcohol produced during fermentation. No need to add sugar as the cider and honey contain plenty!
Pour into (4) sterilized 2 liter bottles (run the bottles through the dishwasher on the rinse cycle without any detergent) filling each about half full (this leaves some room for fermentation) and add 1/4 of the yeast mixture to one bottle. Store the other cider/honey filled bottles for future use. You could probably use (2) 1-gallon milk jugs, each filled half full, with screw on lids, but I've never tried this, so attempt it at your own risk!
Use the 2 liter meade mixture as you would any other DIY CO2 mixture. Once the bubbling ceases ( it will probably only last a week or so) you could filter the yeast and nasties from the meade by pouring it through a coffee filter or paper towel or you could just drink it straight from the bottle
However, if it were me, I would filter it and store it in a cool dark place (maybe under the aquarium) and let it age a bit as the flavor should get better with time.
As a disclaimer, I've never used this method, or any other method, of DIY fermentation, so I'm not sure how well it will work, but I have made a few meades in my day.
Now, why did your CO2 swill remind you of a Miller light? Did you happen to use corn syrup for the sugar in your CO2 mixture? The three major amercan breweries use either corn or rice as an adjunct to their malt in the brewing process. This allows them to save money by using less malt. Corn and rice are very cheap! The one that uses corn has a yellower color than the two who use rice. The addition of more sugar versus malt gives a lighter looking and tasting beer.
A straight sugar/water/yeast combo will be drinkable, assuming it hasn't been contaminated by the aquarium water or other nasties, but I wouldn't try it. Then again, I won't drink beer from the three major brewers here in the US either! If it smells alcoholic or yeasty it is probably OK to drink. But if it smells nasty it probably is. Though I wouldn't try either myself.
Well, Niko, you asked if it could be made any better. Hope my explanation helps you in your quest for a better tasting CO2 mixture
Let me know how it turns out :wink: