Taylor Phenol Red #4 pH Indicator Solution, 2 oz, R-0004-C-144

Taylor #4 is the phenol red pH indicator solution, supplied in a 2 oz dropper bottle. It is listed as R-0004-C-144 and referred to as R-0004, and it is the reagent refill for pH testing in Taylor pool test kits.

What it does

Phenol red is an indicator dye. Add the specified number of drops to a water sample and it develops a color that you read against the comparator block in your kit. The color tells you pH, which is the reading that governs almost everything else in the pool: how well chlorine works, whether the water scales or etches, and whether swimmers come out with stinging eyes.

Replace it every year

Reagents age. Light, heat and time all shift the chemistry inside the bottle, and old solution still returns a color, just not the right one. A reading you trust and should not is worse than no reading, so Taylor recommends refreshing reagents annually.

What this listing is

The 2 oz refill bottle only, for a Taylor kit you already own.