Scale and Stain Controller - is this necessary?

[Jimmie]

Hi. I’ve owned a hot tub for about 3 years and just come across this site and its wealth of information. Incredibly useful and great to understand what actually goes in in the hot tub chemically wise.

However, I’ve not seen mentioned anything about a product by ClearWater called “Stain and Scale Controller”. The ingredient is Etidronic Acid according to the bottle label. No I am guessing as there doesn’t seem to be a mention of this product or something similar that the consensus is that in a balanced tub, it’s not necessary.

My calcium hardness is 234ppm if that’s of any use.

So what are the expert’s thoughts on this stuff? How would it affect the chemistry of the tub/balance? Is it of use or a waste of money?

Dosage is 18ml a week in a 1200litre tub - initial fill dose of 30ml.

Thanks,

Jimmie