Answer:
Carol,

I like to do a 25-50% water change in the spring, followed by netting the leaves and other debris off of the pond bottom. This will reduce the amount of organic matter in the water and will lower the future nutrients that help algae growth.

While the water is still down you can trim back your fish population if needed. Re-pot any plants that are root bound and fertilize them. Clean and start your pumps and bio-filters. Fill the pond and dechlorinate it if needed. Then add your bacteria culture to help out the biofilter (we use BactaPur).I think that about covers most of it.

Thanks and I hope that this was helpful.