Anyone get a brown/grey/blackish film ringing just above waterline in acrylic fiberglass spa? I spa flushed twice, cleaned interior, new filter, and water is perfectly balanced, yet I still get it within days of refill. Ideas? Might this be caused by my cover too tight and not letting air circulate through? Is the bacteria/film further embedded in the plumbing of the spa?
Hey ya Tim 
Welcome to TFP.
That's a scum line- skin cells, oils, hair and body products, etc. Get a good plastic scrubby sponge and wash it down. Its pretty normal.
Try to shower ahead of soaking to limit body lotions and such.
Maddie
Welcome to TFP.That's a scum line- skin cells, oils, hair and body products, etc. Get a good plastic scrubby sponge and wash it down. Its pretty normal.
Try to shower ahead of soaking to limit body lotions and such.
Maddie