I took my tunze 9004 out to clean it and if anyone is familiar with it, it has 4 magnets that is submerged with the skimmer to secure it with exterior magnets. Anyway while cleaning a few magnets that are submerged had some rust on. Not to mention a speck of rust on my glass. Tried cleaning it and soaking in vinegar but it's stubborn. It's a few years old and could always use a better skimmer. Other than that not sure what to do.