I know the sureflow 1600 kit works with the K2, K3, and K4, but is there anything that can be done for the nanos even if it requires alittle cutting? I want more flow in my 15g cube (15.5x15.5x13.75high), but 250gph return+stock koralia nanos just isnt really cuttng it. Don't get me wrong there's turbulent flow and good surface agitation, but I think there needs to be more flow.. I've seen a K4 in a 20high before, but my rock layout I don't think would be very feasible with it and its bulky to boot. I did think about running 2 K2s both with the black impellers in the sureflow kits. If the black impellers can be ran in the nanos with minimal cutting, that'd be really nice too.