White Flakes In Hot Tub - Not Calcium Or Mould

[Millskip]

Hi,
I'm hoping someone can help, I have white flakes in my hot tub water. I carried out some research online and everything points either to calcium deposits or white water mould.

I am fairly confident that they aren't calcium or scale deposits as I have tested for this by leaving a sample containing flakes in a jar overnight in a very acidic solution which was less than 6.2 (that's the lowest my test strips go), but this has not made a difference. Also the shell of my spa isn't rough.

I also don't think they are organic as I have left some in a jar over a period of 3 days now in a highly chlorinated solution (well over 10ppm) and it has made no difference whatsoever.

The flakes are white (no yellowing), no bigger than 5mm across and are super thin, they break easily and are brittle rather than mushy.
I have drained out and refilled the hot tub a couple of times, and cleaned out the filters. We took the panel off the side and some of the clear pipes look white and cloudy - could the flakes be material that has broken away from the pipes?
Any suggestions gratefully received as I am quite stumped!
NB I have tried using a pipe work flush and this didn't work either.

Thanks in advance!

 

[Swampwoman]

This is a "second hand" guess...my hot tub guy was recently replacing the seal on my pump, which had white flaking powder around it.

I had asked if it was salt from summer when I fill with soft water. He said no, it was potassium, and he's seen it before. I don't use MPS, so I didn't quite buy it, but wasn't inquisitive enough to ask him more.

I don't see that in my water, just around equipment, but I thought I'd share

Do you use soft water in your hot tub?

 

[Millskip]

Thanks for your reply!

I'm in a hard water area and we don't have a water softener, this and the fact that it seems to be coating the pipes made me think it was scale - but then I think it would have dissolved with the acidic water in the experiment I did. Also I have read that scale will leave your hot tub feeling rough to touch and it is fine, the water is not cloudy - you wouldn't think there was a problem at all apart from all these white flakes (they are prolific).

Thanks for the tip on the potassium, I don't use MPS either but I'll have a look into it in case it's added to any other hot tub chemicals.