With that kind of fermenter I'd think about racking it to a secondary after initial ferment has finished (take gravity readings). You could get a sheet of plastic (lexan?), drill a hole for grommet/airlock and weigh it down on top of the fermenter for the future. I'm not a big fan of unsealed fermenters in a home brew environment. I've seen many crawling bugs climbing around licking up that spilled wort.
btw I've seen those fermenters used a lot, but it has always been with wine.