And, just to make things interesting, I had a food mishap (my theory, involving a frozen cube and a spill of olive oil on the kitchen countertop) which led to 3 days of madly foaming skimmer---if you have a fairly potent skimmer, you can have a real 'event', which means your sump starts producing foam. I thought I had a really bad problem until I googled 'skimmer foaming' and saw what a bad case looks like. Mine was piffling, 3 days of bubble overflow. I don't know whether anything I did helped, but I attached a very, very fine filter bag, and used another as a receptacle for foam I scooped out after setting the skimmer to 'run dry skimmate', (a laugh.) It was a mess. Today, it is behaving like a skimmer again, and pulling skimmate. Note to self: do not allow that to happen again---ever.