Water Test Reagents
All water test reagents have a shelf life. Powders and crystals are very stable if kept dry. Acids will also last a long time. Storage conditions are more important then date of manufacturer for reagents[1]. Taylor reagents are formulated to last at least one year.
Best Reagent Storage Conditions
- Store reagents at a consistent temperature between 36F-85F (2C-29C)
- Extreme fluctuations cause reagents to deteriorate
- Keep reagents out of prolonged direct sunlight
- Replace caps immediately after use to limit exposure to air and humidity
- Avoid switching bottle caps
- Keep reagent bottle tightly closed[2]
Taylor Technologies says that if you must choose between a hot warehouse (or vehicle trunk) and the refrigerator, opt for the latter for longer-term storage. Keeping reagents in the refrigerator will prolong shelf life. However, once they are taken out, they should be used because subjecting them to constant fluctuations in temperature will cause them to degrade faster. Ideal storage temperatures are between 36°–85° F (2°–29° C), preferably in an environment without big temperature swings.
Recognizing Bad Reagents
- R-0002 DPD #2 - should be colorless; as it goes bad it will change to pink then brown[3]
- R-0003 DPD #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 other 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
- R-0871/R-0872 FAS DPD - Should be colorless; if bad will become increasingly yellow
Other Test Equipment
- Wipe all equipment with a clean dry cloth after use
- Make sure color comparator is in good condition with no fading or staining
- Test vials should be clear and not cracked
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