Enter your pool volume, current FC, and target FC to find out exactly how much chlorine to add.
Liquid sodium hypochlorite (pool bleach) raises FC cleanly — it adds only chlorine and water. Cal-hypo adds calcium, which can cloud water if your calcium hardness is already high. Trichlor adds CYA with every dose, which gradually raises your FC minimum and can lock you into a high-CYA chemistry spiral.
For regular top-offs, liquid chlorine at 10% or 12.5% is the simplest and cheapest option over a season. Cal-hypo is useful if you prefer a granular product or if your calcium hardness is on the low side.
With the pump running, pour liquid chlorine near a return jet or around the perimeter of the pool — never in front of the skimmer, and never mixed with other chemicals. For granular products, pre-dissolve in a bucket of pool water before adding.
All dose formulas work from the same principle: how many grams of available chlorine do you need to raise FC by the target amount, given your pool's water volume?
Concentrations used: Liquid 10% = 0.10 (density 1.074 g/mL), Liquid 12.5% = 0.125 (density 1.094 g/mL), Cal-Hypo 65% = 0.65, Cal-Hypo 73% = 0.73, Trichlor 90% = 0.90.
PoolChem Tracker calculates your chlorine dose automatically from your current readings — no calculator required. It also tracks your history and tells you when to add more.
