I know it's been close to six years since the original post, so my apologies for the delay, but I wanted to post a solution for the common fruit fly situation in case someone new views the forum. I recommend going to your local brew / wine store and picking up the largest fermentation nylon bag. Drape it over the top of the bucket and tie down with a nylon string or twine. It allows oxygen to come and go as the yeast craves it, while at the same time preventing fruit flys due to the micro-gaps in the nylon threading. We do this at our commercial facility and it's worked great for years.