Question 1

How many gallons of 12.5% bleach equal 1 lb of chlorine?

Accepted Answer

12.5% NaOCl provides 1.0425 lb of available chlorine per gallon, so 1 lb of chlorine ≈ 0.96 gal of 12.5% bleach.

Question 2

Does 12.5% bleach lose strength?

Accepted Answer

Yes. Sodium hypochlorite degrades roughly 1% per week at 70 °F and faster in heat or sunlight. Re-test strength monthly and adjust pump output.

Question 3

Can I use this for swimming pool chlorine?

Accepted Answer

Yes — the math is identical for any aqueous chlorine source. Just enter the correct trade strength (5.25% household bleach, 10% pool, 12.5% industrial).

Question 4

Why isn't density 8.34 for strong bleach?

Accepted Answer

Industrial 12.5% NaOCl is ~1.20 SG (10 lb/gal), but the pounds formula uses 8.34 because we're tracking the chlorine fraction, not the solution.

Sodium Hypochlorite (Bleach) Dose Calculator – Gallons/Day