Fluoride addition and pH

[djcbgn]

Hello,

I am working on a drinking water well for which the City requires adding fluoride (fluorosilicic acid). My understanding is that fluoride addition will not depress the pH enough to add another chemical like caustic for pH adjustment. I am waiting on the water quality report from the test well, so this may provide additional useful information. I am thinking of adding a spot in the chemical building for caustic and the city can add this later if they want. Please let me know what you think. Also, after the fluoride addition we will add sodium hypochlorite.

Thanks.

David

 

[bimr]

The amount of fluoride added is only 0.7 milligrams per Liter. The pH will drop only slightly and the extent of the slight drop will depend on the parameters of the water (alkalinity). Can't imagine that the drop will be more than 0.05-0.1 pH units.

Have never seen any utility add caustic for this purpose. If you are concerned about it, have a laboratory do a test.

 

[djcbgn]

Thank you for your input.

 

[EdStainless]

Having the correct pH for the effectiveness of the Hypo is a bigger deal.

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P.E. Metallurgy, consulting work welcomed