[kingkong]

Quote: Originally Posted by Nancy M. I thought Muriatic acid was used to help leach out the lime in concrete? and that if a pond had High PH you could add small amounts of it to lower ph or to stablize it? Also correct me if I have been misinformed.

I will try. Muriatic (HCl) acid does react to alkaline materials such as lime. That is why it is used to "etch" the existing concrete surface to pit it creating a better bonding surface for adhesion of new product coating.

HCl has a ph less than 7 probably around 2, so if added to pond water of a Ph of 8 it would for sure lower it to a degree.

If you etch with HCl, flush the acid reidue well with water. Then you can neutralize the remaining acid residue and salts with a base detergent or liquid bleach. Then it would be a good idea to use a salt remover with a stiff brush. The salt residue can interfere with adhesion of a new coating.