Look in the QRH for the unreliable airspeed checklist, it will have pitch and power settings for various speeds and configs. Speed decay in turns can be countered by adding a few percent N1 as you start to roll into the turn. It sounds as though you are over controlling. Smoothly roll on 25 degrees of bank, but imagine you are trying not to spill a drop of your passengers G&Ts not emulating the roll rate of a fighter.
If you fly smoothly you shouldn’t see the arrow.