Weird white powder in spa

[RawhideKid]

Hi all! Long time since I've posted, because I haven't really had any major issues.
However, the last six months or so I've had this weird powder build up in my spa that spills over into my pool. It build up quickly - in a week I can get a pile 2-3 inches deep, by 12 by 12 inches - only in the spa. I scoope it out and it looks like, well, potato flake that haven't dissolved in the water. Kinda feel mineral-like.

I've also replaced my chlorine generator, and although I've cranked it up to 100%, I'm struggling to maintain my chlorine. I added some stabilizer since my CYA levels were low though, so perhaps that will help. Any thoughts on this powder? I can post other test results later in the week when home, but as I recall they were all normal.

Photo of powder when scooped out and put on pool deck and let dry:


Photo of pile of powder by drain:


Thanks for any thoughts here!

RHK

 

[JoyfulNoise]

Drop some in diluted MA and see if it fizzles. If it does, it's calcium scale. Could be related to your 100% SWG settings. If your struggling to maintain FC, do an overnight chlorine loss test, you probably are fighting a nascent algae bloom. SWGs are easily overwhelmed with algae.