well if it were so self explanatory,the question wouldn't been asked,the Aquaero works off 4 and 3 pin fans and the 3 pin do have a rpm signal and not knowing the aquaero i don't know if it is a concern
but thanks for the lack of help.
As you described in the question the fan has a ground and + wire. No RPM
3 pin fans have ground, + and sense/RPM wires.
4 pin fans have ground, +, RPM and PWM wires.
If you are building an enthusiest PC with watercooling a little googling on how things work goes a long way.
http://pcbheaven.com/wikipages/How_PC_Fans_Work/