Hi all,

I am pretty hopeless at chemistry, but I am sure you can help.

I have a small spa pool (1000L) that I emptied 10 days ago, after using 250ml of Swirl Away (https://bioguard.com.au/products/swirl-away/) to clean it.   The pool was completely emptied and dried, then re-filled.

I then used a standard chemical mix once it was refilled:

1 Tablespoon of Aquality (1000g/kg Sodium Hydrogen Sulphate)

250g of Performance Up (1000g/kg Sodium Hydrogen Carbonate)

150g of Spa Sheild (740g/kg of Calcium Chloride)

2 Tablespoons of Swim Clear (650g/kg Chlorine)

And then I went on holiday.  When I came back today, the normally smooth surface of the fibreglass spa was rough to touch (kids said it felt like sandpaper).   This covered the entire spa surface, along with the metal jets, etc.  Everything below the water line was covered.

If I rub really hard, it seems to come away.

Any ideas what this is?

Any quick way to dissolve it?