Chlorine & Chloramine

Municipal water disinfectants that are highly toxic to fish - must be neutralised via water conditioner before adding tap water to aquariums.

Unit: ppm Code: CHLORINE

📖 Overview

Municipal water is disinfected with chlorine or (increasingly) chloramine - both of which are lethal to fish and beneficial bacteria at trace concentrations. Chlorine evaporates in 24-48 hours if aerated. Chloramine is stable - only chemical neutralisation (dechlorinator) removes it. Never add untreated tap water to a fish tank.

❓ Why It Matters

Kills nitrifying bacteria (crashes cycles). Burns gills. Even trace levels stress fish over time.

🧪 Testing Methods

Chlorine test strips (rough). Digital chlorine meter (precise). Salifert Chlorine Test (aquarium industry standard).

📉 How to Lower

Water conditioner (Seachem Prime, API Stress Coat). Activated carbon (removes chlorine but not chloramine bond). Aging tap water 24 hours (chlorine only).