Photometric determination of ortho-phosphate. • Photometric determination of the yellow phosphate-molybdate-vanadate complex in acidic solution. • ortho-phosphate ions react with molybdate/ vanadate to form a yellow phosphate-molybdate-vanadate complex. • Type: standard test 1-78 • Range: 10 mm cuvette: 1 - 17 mg/l PO4-P / 2 - 50 mg/l PO43- 50 mm cuvette: 0.2 - 6.6 mg/l PO4-P / 0.5 - 20.0 mg/l PO43- • Sufficient for: 440 determinations • Sea water suitability: yes