By chance have you used any magnesium chloride or magnesium sulfate in your pool? Do you happen to know the total hardness (Ca + Mg hardness ) of your water? Australian pools/owners tend to utilize magnesium chloride and Epsom salt (magnesium sulfate) in their pools.
These newish ’mineral‘ salts or ‘mineral crystals’ as they call them are “amazing”, they can even predict the lotto numbers… so I’m told.
Most of the major suppliers have a range, Fluidra, WaterCo, Zodiac, etc. all with the cheesiest marketing I’ve ever seen. One is 98% MgCl2.6H20, while the others are blends that also include KCl, NaCl and borax. The only thing that they don’t include is magnesium sulfate, it must be too expensive.
Apparently there’s no salt in magnesium chloride but an existing chlorinator will run on it just fine… must be magic. Cant be witchcraft, chlorinators don’t float.
These new mag salts are about 10X the price of our regular salts and are only 98% pure for the better ones while our regular salt is 99.4%. Pay more, get less.