New intex 15ft metal frame pool owner...we started the pool with the included sand filter and just converted to a SWG. Just got a vacuum and started using it right away. However, I began picking up little red worms. I researched them to be bloodworms that are not harmful to humans. They are the larvae of midges. Has anyone encountered this and how do I get rid of them? Does this mean my filter is not doing its job?