Dichlor (granular stabilized chlorine)
Also called: sodium dichlor, stabilized granular chlorine, dichlor shock.
Dichlor is a granular chlorine, about 56–62% strength, that adds cyanuric acid (CYA) with every dose. It raises free chlorine and stabilizer together, which makes it a startup tool rather than an everyday chlorine or a routine shock.
Why it matters
Dichlor's side effect is the point when you want it. At startup it raises chlorine and CYA together to your target in one product. Used week after week as shock, the CYA accumulates until your chlorine is over-stabilized and stops working, and the only way CYA comes down is draining and replacing water. Branded shock is usually cal-hypo or a dichlor blend. When you just need chlorine fast, plain liquid chlorine raises free chlorine without adding CYA or calcium.
In numbers
About 22 ounces of 62% dichlor raises free chlorine by 10 ppm in 10,000 gallons, and adds stabilizer (CYA) along with it.