Same 2 problems I am having. For the "white" stuff, check around your fittings (nozzles, filter intake, etc) and see if there is a buildup there. Almost like caulk, but it will come off if you rub it. Sort of greasy, almost like a really, really heavy hand cream. I am getting that in my spa this year, first time I've had it happen. Shocking (with bleach) seems to clear up what is floating in the water, but not what is on the fittings.
And, we are getting a funky smell as well. New this year. Very much like you described, plasticy but not disgusting or rancid. Seems to go way down after the cover has been off for a while, but still noticeable.
So, I am going to do 2 things, as per the manual. First, drain and refill - while using a product called Swirl Away. It is supposed to be a spa cleaner that doesn't foam and cleans out all the pipes etc. My manual says to use it for each fill, but I've never done it yet (partway through year 3 with the spa, probably 5 refills). Plus a good manual scrub down.
Second, I am replacing the filter. That is supposed to be once a year but there is no local source so I have to get it delivered. I have cleaned the filter, but after almost 2 years, I think there are things in there that don't want to get cleaned! Then I'm going to stick with BBB again for at least a while to see how things work out.
I am guessing that BBB really has nothing to do with my problems. I think it is just time to really clean that sucker. The problem with just using DiChlor is that the CYA shoots up very quickly, I had readings over 100+ in less than a month. Per everything I've read, that can severely reduce the effectiveness of the CL.
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