What's a good filter for a 20 gallon?

I've heard of it done, but an AC70 or 110 on a 20g tank is a LOT of water movement. Not sure if it was here, but one dude claimed to have had an AC110 on a 10g. Talk about glass face plant..

That what I think too, Joel!! There is such a think as too much flow even for my hillstream fish!
 
I have both a 20 long and 20 high, eheim canisters on both. ECCO 2232 and 2213. Plenty filter for this size and are not hard to clean.
 
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