VISOCOLOR® HE Silica • Colorimetric determination of silica • In acidic solution soluble silica or silicates react with ammonium molybdate to form yellow silicomolybdic acid, which is reduced to silico-molybdenum blue with a reducing agent. • Phosphates interfere only in high concentrations (> 30 mg/l PO43-). (Reaction principle analogous to APHA 4500-SI-E, DIN EN ISO 16264-H57) • Type: high sensitive test kit • Range: 0.0 · 0.01 · 0.02 · 0.03 · 0.05 · 0.07 · 0.10 · 0.15 · 0.20 · 0.30 mg/l Si • Sufficient for: 120 determinations • Shelf life at least: 24 months • Sea water suitability: yes • Detectable with PF-11: no • Natural water contains silica in different amounts, depending on the geological conditions the water encounters during its course. • The silica occurs partly as soluble silicate, partly colloidal as polysilicic acids. • The silica content in water for medium and high pressure boilers may not exceed certain limits; in power plants therefore constant measurement of the silica content is required.