I've made my own air-powered internals which are cheap as chips to make and safer as they can't leak on your floor but it'd be a bit hard to make one with enough grunt for 200L. Can post a pic if you want. I usually make them when I want a really tiny tiny filter for a small tank, the biggest one I am running is on a 45L but it does work really well.
There are videos on youtube of canister and other filters being made, and lots of aquarium sites have something, google DIY canister filter would be my suggestion