If you can afford it and don't mind a little noise, two MP40s would be ideal for that tank. Since your tank is only 75g, you wouldn't need to run them at 100% to get good flow. If you want it to be absolutely silent, two Tunze 6095s would give you a nice wide/gentle flow, especially if you can control them with an APEX or pick up a used 7095 or 7096 controller on the cheap. Either of those options will set you back $500-$700. I own both of the powerheads I suggested and can't recommend one over the other. They both have their advantages. Jebao powerheads seem to be the rage at the moment. Someone will probably suggest a WP25 or two, which might work great and only set you back about $150. I do not own any of the Jebao powerheads, so I cannot recommend them without reservation.