Trichlor
Trichlor (trichloroisocyanuric acid) is a slow-dissolving stabilised chlorine tablet that delivers free chlorine and cyanuric acid simultaneously.
In Plain Language
Trichlor tablets contain approximately 90% available chlorine and are strongly acidic (pH ~2.8 in solution). Each tablet adds CYA as it dissolves. Used as the primary sanitiser, trichlor is very convenient but leads to CYA accumulation over a season. It also lowers pH, requiring more frequent pH correction. Trichlor is not suitable for use as a shock product because the CYA addition makes high-dose treatments impractical.
Why It Matters
Trichlor is the most widely used pool sanitiser product, but its CYA contribution is chronically under-monitored, leading to the most common long-term pool management problem.
Typical Values
Last reviewed: 2026-06-01