I started a bucket of liquid compost for plants I don't want in the other composts. I haven't had a lid on it and now it's got these larvae/maggoty things living it. They're whitish, a couple of centimetres long when at their biggest, and they have thin tails maybe a cm long. They seem to swim around a bit. Kinda creepy but intriguing too. Any idea what they are, and what if anything I can do about them? I guess I should cover the bin... hot dry inland maritime climate, approaching summer.