After completion of the hearing required by section 23-3531, the county board shall order such changes in the boundaries of such proposed district or of the areas into which such proposed district is to be divided as it deems proper, but no such change shall reduce the total taxable valuation of all taxable property within such proposed district below eight million six hundred thousand dollars. The county board shall also order that the question of the formation of such district, as set forth in the petition and any changes therein ordered by the board, shall be submitted to the electors of such proposed district at a special election to be held for that purpose and shall set a date when such election shall be held at the usual voting place within each precinct. The county board shall certify such question to the county clerk or election commissioner who shall give notice of such election in the manner provided by law for the conduct of special elections.