Did you save the old water?
We don't usually suggest draining and cleaning a fish pond unless there was a chemical spill or the pond was terribly ignored and full of nasty muck and dead fish.
By power washing you washed off all the natural beneficial biofilm and bacteria needed for a well balanced ecosystem.
What's done is done, but now you will have to restart everything.
You will most likely end up with green water soon after refilling it, but that's ok, it's just nature's way of balancing out the water by adding algae to rid the pond of the excess nutrients formed by the fish waste. We call it new pond syndrome.
It's going to take a while to get the ecosystem back up and running. You will need lots of plants and good filtration.
Forget about store bought beneficial bacteria. To me, it's a waste of money. Your pond will develop it's own. It just takes time.