Muriatic Acid comes in liquid form, While we have Muriatic acid in Gel - Viscous form which is resulting with the excess blend of surfactant and a thickening agent, which is not only increasing importance to use on the vertical surface where liquid use is not possible but also increasing cleaning action without smoke generation.
During uses of Muriatic Acid in liquid form, fumes are coming, which is creating the problem for handling personnel and liquid phase of muriatic acid can't be used properly on the vertical surface. While viscous muriatic acid is free from fumes and easy to apply on vertical surfaces.