How do I put bottom drain dome cover back on?
 

While cleaning out my pond, I accidentally hooked the bottom drain
dome cover and pulled it off. My pond is close to 6' deep at the
drain and the water is only about 58 degrees - way too cold to swim
in. I really don't want to have to drain the pond. I'm hoping
someone might have an idea of how to do it. Any suggestions would be
greatly appreciated.