My wife is insisting on training the dogs to swim, with safety as the advertised reason, although she has visions of a mermaid with her seadogs. She countered my bad for the filter argument with the trainers suggestion of a nylon filter saver to catch the hair at the skimmer. I'm a smart man who knows when he's lost, the dogs are destined to swim. so my question is, would these covers be bad for the filter by obstructing flow? Or as long as I keep them clean would they help?