Ya, i think Gouldian is right. The penductor is busy for return outlets which you don't use wavemaker.. it supposedly give a 400% boost so the flow is actually quite strong.
http://www.aquariumspecialty.com/catalog/product_info.php?cPath=48_176&products_id=2362&osCsid=cad2f12ab4836d616e6044cdf761a0ad
Think is this... called penductors instead.
Lemon, i saw on BBC they went to this "blue hole" and found a few new species... One of it is this Luminous Blue Dot Damsel fish... did you watch it? I think they found a new species of flame hawk also:P
Our return is fitted with 2 of these.. based on the write up i think it generate like 3 times the power and we did feel it so in that respect i think it works..