BOTZ melting point reducer (SPS) is an additive for stoneware glazes, in order to reduce the melting point of the glaze by approx. 100°C- Mixing ratio: usually 3 teaspoons of SPS on 200ml glaze -Mixing ratios 9870, 9873, 9898, 9899: 1,5 teaspoons only on 200ml - Caution: glaze colours change gradually! - Recommended firing temperature: 1150°C / soak 30 min.