A few newer designs coming out that take away from the typical updraft problems.
http://reefbuilders.com/2011/12/09/r...ellet-reactor/
The recirculating design is great IMO, you can blast your pellets and not have to have all that water flowing through the reactor, instead you can set your output hose to a nice steady flow.
http://www.advancedaquarist.com/blog...ic-bio-reactor
this is another great design, it is not recirculating, but takes out the flow limits of the downspout.