What is the optimum pH for the Hach silica methods 8185 and 8186?
pH for silica testing
The silica reaction is performed under acidic conditions with the reagents lowering the pH of the sample to a pH of about 2. If the sample is very basic or highly buffered, the reagent may not be able to acidify it. If this is the case,you canneutralizeyour sample with nitric or hydrochloric acid to a pH of 7, then the reagent should be able to bring it down to a pH of 2.