We had the same problem with our tub. Ended up draining (not just because of the scum) and refilling after 1 month (as Chas will surely tell you to do 
) We also put in a Dirty Duck and have not had a problem since. I do know that the one time I use the Brite and Clear it left a bad scum line in the tub.
My reputation preceeds me again.
Yes, I do tell our customers to drain and refill a new tub at about the one-month point. It helps with all sorts of things, in fact I push it even for folks who are not having any problems at all.
As to the mention of "Bright and Clear," the product did what it was designed to do. If you add B&C to just about any tub, it will bring out some amount of soaps and oils: that's what it is desinged to do. It will deposit those fun little items on the waterline just above the water, so you can wipe them away with a soft towel. It will cause foaming if you overdo it. I usually only add it as needed.
As to the brown stain around the drain fitting: that's an iron reaction. The ozone is oxidizing iron out of the water and that's where it often shows up. You can add a product like "Metal Gon" by Liesure Time, or a similar product. The entire bottle of Metal Gon should be poured in after you do that water change.
Ironic note: I have a Vista Pearl with Coastal Gray siding, but it will be removed from my yard today, weather permitting. I have some folks interested in buying it, and I want to polish it up and put it on my showroom floor so they don't have to come to my house to see it in action.
I'm going to ask the guys to put one of the used tubs we have on hand in my yard so I don't have to go without a spa until the new one arrives.
