Citric acid or hydrochloric
Both kits do the same thing and take the same number of drops. The choice is about what you would rather have in the cupboard.
| Citric acid | Hydrochloric | |
|---|---|---|
| Strength in the bottle | 50% | 4.375% |
| Chlorine dioxide produced | The same | The same |
| What it is | A weak acid, food grade, derived from cassava root — the preservative and sour note in a great many foods | The acid present in the stomach's own digestive enzymes; ours is chemically derived, food and pharmaceutical grade |
| At high concentration | Will not dissolve flesh | Can dissolve flesh — treat it with the respect any acid deserves |
| Reaction | Milder | Faster |
| Drops to use | Identical | Identical |
So which one
If the kit lives in a kitchen cupboard or travels with a family, citric acid is the easier thing to own: it is the same acid that keeps jam from spoiling. If you want the reaction to move along and you are comfortable handling an acid, hydrochloric is the faster of the two. Neither choice changes the dose or the result.
From the manufacturer's own FAQ at KVLab (Keavys Corner LLC), who state that citric acid at 50% and hydrochloric at 4.375% produce the same amount of chlorine dioxide when mixed with Part A.