Fwiw, I think floss is amazing media. It's also the cheapest media. I use a sponge, a bag of broken lava rock [ instead of ceramic media, it does the same task], with floss on top, in my AC70s.
I don't toss the floss very often. I clean it just as I do the sponge, and put it back. I don't replace it until it begins to fall into smalls shreds, at which point it gets a bit harder to handle. It will also be quite a dark colour by this point. I often wrap the floss in a section of soft plastic netting, which I get from taking a bath puff apart. Keeps it together and makes it easier to handle when it's getting a bit beat up.
I don't replace old floss at once either. Once it's got to the point it needs to be replaced, I'll remove roughly half, and wrap a new piece of floss around the remaining old pieces.
Week or two later, I'll replace the remaining oldest floss and wrap another new piece around the earlier replacement piece. I think the big roll I have is likely going to last me at least five years or more.
I buy floss by the big bag, in a large roll. I tear chunks off that when I need new media.
I also use pieces of this to seed new filters, along with the rinsings from cleaning filters, and it works very well.
I just can't see throwing out perfectly useful floss because it's no longer bright white in c colour. So it turns grey... who cares ? By the time it's getting ragged, and dark grey, it is losing it's ability to polish water as well as it can when new, but until then, I keep using it. It does grow plenty of BB.. I have no real idea how many compared to ceramic or sponge, but I've yet to have any issues with BB being too few.
Edit. It's quite easy to make your own filter bags from almost any fine netting, even if you aren't a great stitcher. Fish line makes good, non rotting thread, just as it does for tying moss on rocks, and you can buy net from fabric stores.. tulle or craft net works well, usually made of nylon or polyester. Or take apart a cheap lingerie wash bag from the dollar store. Some are coarser net, some are very, very fine, almost like brine shrimp netting. The coarser stuff is better for ceramic media, but the brine shrimp type is great for things with smaller grains. It gets clogged faster though, and need cleaning more often.