Starter chemicals
Last reviewed August 12, 2026
What to carry and what it does
Doses are per 15,000 gallons. Scale to the pool in front of you: 30,000 gallons takes double, 10,000 two thirds.
| Chemical | Moves | Dose per 15,000 gal |
|---|---|---|
| Liquid chlorine, 12.5% | Free chlorine up | 12 oz → +2 ppm |
| Muriatic acid, 31.45% | pH down (and TA) | 12 oz → −0.2 pH |
| Soda ash | pH up | 6 oz → +0.2 pH |
| Baking soda | Total alkalinity up | 1.5 lb → +10 ppm |
| Calcium chloride | Calcium hardness up | 1.3 lb → +10 ppm |
| Stabilizer (granular CYA) | CYA up | 1.3 lb → +10 ppm |
| Pool salt | Salt up (SWG pools) | 1 lb per 1,000 gal → +120 ppm |
A one-gallon jug of liquid chlorine is 128 oz. A bag of salt is 40 lb, which moves a 15,000-gallon pool 320 ppm.
Buy the strength, not the label
Liquid chlorine sold as "pool shock" at a big-box store is often 10% or weaker, and it loses strength on the shelf. Trade supply is 12.5% and fresher. Every dose in these guides assumes 12.5% and 31.45% acid — at 10% chlorine you need a quarter more.
Liquid chlorine degrades in heat and light. A jug that has sat on a hot truck for three weeks is not the strength on the label. Buy what you will use.
The two that need care
Calcium chloride heats up as it dissolves. Mix it in a bucket, don't hold the bucket against you, and pour it into the deep end.
Cal-hypo: know when not to
Granular cal-hypo is cheap shock and it has two hard exclusions. Not in a vinyl pool — it bleaches a permanent white mark on the liner. Not in a salt pool — it adds calcium, and salt pools already trend high, which scales the cell.
On those pools use liquid, or pre-dissolve cal-hypo in a bucket first. On plaster with normal calcium it is fine.
What you don't need every week
- Phosphate remover — only when algae keeps returning on a pool whose chlorine is already right. See phosphates.
- Algaecide — correct chlorine prevents algae. Algaecide treats a symptom of chlorine being wrong.
- Clarifier — cloudy water is a filter problem, not a chemistry one.
- Stabilizer — monthly at most. It only leaves with water, so it accumulates. See cyanuric acid.
The pools that need the fewest extras are the ones where chlorine, pH and alkalinity are already in range. Most add-on products are sold against problems those three prevent.
Logging chemistry on every stop? PoolSpartan keeps the readings, works out the LSI as you type them, and sends the customer a service report when you close the visit. Free to start. We only get paid when you do.
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