I seem to have developed a white film on the surface of my water. You can’t see it from the top, but it is prevalent when you look from the bottom. I recently switched salt mixture to Aquacraft Bio Marine Salt Mix. That’s the only thing I’ve done different. I contacted the owner, Michael De Preet, he said they don’t put anything in their salt to cause a film, so I don’know. Any ideas. I treat with a bag of Phosgard and dose Red Sea NO3PO4. Any ideas?