Pool Chemical Compatibility Chart
What never to mix, and how to shelve what you own.
Updated · Reviewed by the Skimmer editorial team
Pool chemical injuries send roughly 4,500 people a year to US emergency rooms, according to the CDC. Most happen while handling or mixing products, not swimming.
Pick what you own
| Trichlor | Cal-hypo | Liquid Cl | Muriatic | Soda ash | Baking soda | |
|---|---|---|---|---|---|---|
| Trichlor | ||||||
| Cal-hypo | ||||||
| Liquid Cl | ||||||
| Muriatic | ||||||
| Soda ash | ||||||
| Baking soda |
Your shelf layout
Liquids on the lowest shelf, tabs and powders above them. Cal-hypo in its own sealed bin, never touching trichlor or dichlor.
- Liquid chlorine / bleach (bottom shelf)
- Trichlor tabs
- Cal-hypo shock (own sealed bin)
Floor level or the lowest shelf, in a plastic tub that would catch a leak. Away from metal tools; acid fumes rust them.
- Muriatic acid
Powders above liquids. Nothing here reacts dangerously with the rest, but keep each sealed and labeled.
- Soda ash (pH up)
- Baking soda (TA up)
Never mix
- Chlorine products with acid: releases toxic chlorine gas.
- Cal-hypo with trichlor or dichlor: can ignite or explode. Never in the same feeder or skimmer.
- Any pool chemical with household cleaners, ammonia or solvents.
- Never add water to chemicals. Add chemicals to water.
Safe storage
- Cool, dry, ventilated place out of direct sun, ideally a locked shed outside the house
- Every product in its original, labeled container with the lid on
- Oxidizers (chlorine) and acids on opposite sides, with real distance
- Liquids below powders, so a leak never drips into them
- Away from fuel, fertilizer, the pool heater and the grill
- Up high or locked, away from kids and pets
- One clean scoop per chemical; never share scoops
Where to store: shed, garage or house
A ventilated shed away from the house is best. A garage works if the chemicals sit away from the car, fuel cans and lawn products, and the space does not get hot. Never store pool chemicals inside the house, under a deck, or in the equipment pad enclosure next to the heater.
Ventilation
Liquid chlorine and muriatic acid both give off fumes. Passive vents high and low in a shed are enough for most homes. Do not seal liquid chlorine in an airtight bin: it vents gas as it ages. Acid fumes rust metal shelves and tools, so keep acid in a plastic tub on the floor.
Shelf life and heat
Liquid chlorine loses strength quickly, faster in heat: a jug stored in a hot shed can lose a third of its strength in a month or two. Buy what you will use in a few weeks. Tabs, cal-hypo and balancers keep for years if dry and sealed.
Spill or exposure: what to do
- 1Get people and pets away and upwind. If you smell strong chlorine, leave the area.
- 2Do not add water to a dry spill, and do not mix spills. Sweep dry spills into a clean, dry container.
- 3Rinse skin or eyes with clean running water for 15 minutes.
- 4Call Poison Control at 1-800-222-1222 (US) for any exposure.
- 5Call 911 for trouble breathing, a fire, or a large spill.
Note: Disposal: take unwanted pool chemicals to a local household hazardous waste drop-off. Never put them in the trash, down a drain or into the pool to get rid of them.
Handling
- Add chemicals with the pump running, one at a time
- Wait between different chemicals; never combine in the skimmer
- Never put cal-hypo and trichlor in the same feeder or skimmer
- Wear eye protection and gloves; measure, don't eyeball
- Follow the product label, it overrides any general rule
Sources
Figures and safety guidance on this page draw on the following public references.
- 1.U.S. Environmental Protection Agency. Pesticide Registration (Antimicrobials & Sanitizers)
- 2.U.S. Centers for Disease Control and Prevention. Healthy Swimming: Pool Chemistry & Disinfection
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General reference for residential pools. Product labels and local guidance override any figure here. See our methodology and editorial policy. Skimmer · skimmer pool care.