Use the CuLator permanently. If you use it UNDER a skimmer sock, it shouldn't get gummed up. And, it can help with the small amounts of metal you add each time you add water. Probably the best thing would be to add a small amount of HEDP (NOT, a regular dose) simultaneously with any fill up -- to keep the metal in solution, and then to put the CuLator back in. The CuLators should be able to 'grab' the iron away from the HEDP, so it never becomes a problem.

Marie (mbar) who's been the stain guru around here for a long time, reported she was no longer getting iron stain build up over the season, once she started using the CuLator.