All water test reagents have a shelf life. Powders and crystals are very stable if kept dry. Acids last long. Storage conditions ae more important then date of manufacturer for reagents[1]. Taylor reagents are formulated to last at least one year.
Reagent Storage Conditions
- Store reagents at a consistent temperature between 36F-85F (2C-29C)
- Extreme fluctuations cause reagents to deteriorate
- Keep reagents out or prolonged direct sunlight
- Replace caps immediately after use to limit exposure to air and humidity
- Avoid switching bottle caps
Recognizing Bad Reagents
- R-0002 DPD #2 - should be colorless; as it goes bad it will change to pink then brown[2]
- R-0003DPD #3 - should be colorless; as it degrades it will become yellow
- R-0004 pH Indicator - as it degrades it turned from red to yellow or purple
- R-0008 TA Indicator - should be dark green; begins to stain the milky bottle as it goes bad
R-0011L - CH Indicator - should be deep blue color; any otehr color indicates it is bad R-0718 Silver Nitrate Indicator - should be colorless; no easy way to tell if bad and recommended to replace annually T-0871/R0872 FAS DPD - Should be colorless; if bad will become increasingly yellow
