Both raise free chlorine. The difference is what else they put in your water, and how they handle.
The short answer: liquid chlorine adds only chlorine and a small amount of salt (TroubleFreePool), but it loses strength in storage. Granules are dichlor, which adds stabilizer, or cal-hypo, which adds calcium. If your stabilizer or calcium is already high, liquid is the better fit.
Part of: Pool Chlorine: Types, Levels and How to Keep Them Steady, our overview of every chlorine question.
Side by side
| Liquid chlorine | Dichlor granules | Cal-hypo granules | |
|---|---|---|---|
| Also adds | A small amount of salt | Stabilizer (CYA) | Calcium (about 1/3 of the product) |
| pH effect | see note | Lowers pH | see note |
| Storage | Loses strength: 12.5% about one month, 6% about six months at full strength | By the label | By the label |
| Good for (our reading) | Pools with enough stabilizer; salt and liquid-chlorine routines | Pools that still need stabilizer | Pools with low calcium |
From TroubleFreePool ("How to chlorinate your pool", "Recommended pool chemicals"). The pH effect of liquid chlorine and cal-hypo is not covered by the sources we read; test pH after you add any chlorine (our advice).
When liquid chlorine fits
TroubleFreePool's summary: liquid chlorine or a salt chlorine generator are the two best options. Liquid is the same chemical as household bleach, sold stronger: 10% or 12.5% instead of about 6%.
As an Amazon Associate we earn from qualifying purchases. We have not tested these products.
Raises free chlorine Liquid chlorine (sodium hypochlorite)Sold as "liquid chlorine" or "chlorinating liquid". Check the strength (%) on the label: the dose depends on it. Shipping rules differ by product and state.
When granules fit
Granules store more easily and are easy to measure by weight (our note). Dichlor fits a pool that still needs stabilizer; TroubleFreePool warns it can raise CYA very quickly. Cal-hypo fits a pool that needs calcium; TroubleFreePool notes the calcium "goes into your pool water and you can't get it out."
As an Amazon Associate we earn from qualifying purchases. We have not tested these products.
Granular chlorine Chlorinating granules (dichlor)Fast-dissolving granules. Dichlor adds stabilizer (CYA); calcium hypochlorite adds calcium. Check the active ingredient on the label.
Sources
- TroubleFreePool: How to chlorinate your pool (what each type adds, dichlor raises CYA quickly, cal-hypo calcium, best options)
- TroubleFreePool: Recommended pool chemicals (strengths, storage time, same chemical as bleach)
- TroubleFreePool: SLAM process (cal-hypo adds calcium, dichlor adds CYA)
Sources read on November 4, 2026. Product labels change: the label on the product you buy always wins.
