It seems that floating food is the most commonly desired type for the average pond steward since we can see the fish feeding. Since you are currently feeding the sinking kind, I think I would start mixing in some floating food with it and gradually wean them to the top of the water.

I don't think it matters much to the fish, I just like knowing that they are eating the food. A good rule of thumb is to feed NO more than the fish will eat in 15 minutes. You can't tell if they are eating off the bottom (assuming that your water is not crystal clear).

Fish on!,
Noel