hi chris,
high flow is possible only when the chaeto is very healthy, in long strands and curled up in a tumbling ball. most fuges encourage it to grow in a sectioned portion of their sump that just receives slow laminar flow. this causes chaeto to grow to fill the container...and i have found that the chaeto strands are weaker and more brittle.
i actually stumbled on the bucket idea because i didnt really have a choice as when i made my first one, my tank was already up and running and i wanted something simple, quick and, by lucky chance, cheap!
how i have my output nozzle is it has a 90 degree elbow and it is directed at a 45 degree angle to the side of the bucket. the jet of water hits the side, is directed to the bottom and comes back up. this sets a circular water pattern that will tumble chaeto.
if just starting out with the bucket idea...start with a small ball of chaeto. almost for sure, if the chaeto is from slow flow fuges, the strands will be thin and brittle. this is where a lot of people just plop this brittle mass into a high flow fuge with nothing but destructive results...and the clogging of pumps as you have seen. been there...done that!
thus, start with a small ball with a slower swirl water current. the swirling will be more gentle on the chaeto ball. as the ball grows, you should notice the chaeto strands becoming thicker, denser and stronger. this is when you can start increasing the flow.
my chaeto ball doesnt get stuck in the drain. to prevent this, you place the drain high enough (same level as input) AND if you can get the ball to spin in the lower part of the bucket. a little trial and error and you will find the perfect angle of the nozzle to do this.
what is the big deal about getting the chaeto to spin? i found that chaeto that sits in fuge sumps, the bottom of the chaeto colony starts to die because it doesnt receive enough flow or light...esp light. thus, what does a spinning ball do? yep, it allows illumination all over the chaeto. there is no bottom. max efficiency of growth. BUT...dont let your ball get to big or the center will not receive enough light.
i light my fuge for 18 hours a day with a lights of america 65w 6500k setup and couldnt be happier with it.
hope this is helpful! i have been using bucket fuges for 4 or 5 years now with nothing but excellent results!!!