I dont like remoras because they are a venturi/nozzle design. The restriction used to suck in air produces alot of back pressure on the pumps. Now, on larger, shaft driven pumps like iwaki's and their like, the back pressure isnt so bad (like with a beckett), but on little pumps that suck at dealing with back-pressure in the first place, the output is greatly reduced.
Thats why needlwewheels like the CoralifeSS are the best for smaller tanks... needlewheels are able to make 2-3x the bubbles with the same pump when compared to a pressure-induction system (venturi, beckett, downdraft, etc).
One mod my cousin did on his urchin (in sump remora) was to remove the nozzle all together, and replace the pump with a needlewheel MJ1200... easily 3x the bubbles.