Today i began to restart my pond from the recent cooler months, i noticed a vague smell of rotten eggs and the only thing it could be is hydrogen sulfide. There are no fish in the pond, they are all in my garage for the next two months while the temp gets warmer. In order to get rid of it completely, should i drain all the water and remove the thin layer of decomposed organic matter probably laying on the bottom(Pond is bare bottom)?