Well it looks like my 'upgrade' pump Sicce Syncra silent 0.5 does not fit in the pump chamber. I'm a little confused about this because saltwateraquarium.com sells the waterbox 10 cube with the syncra silent 1.0 pump as an optional upgrade package when purchasing the tank. I thought that the 0.5 would be a safe bet if the 1.0 model fits.
Sicce has a nano pump model, but it's rated for less GPH than the stock pump that came with the tank.