R-0004 is the pH indicator reagent used in the Taylor K-2000 series kits (i.e. K-2005, K-2006, K-2006-C). 5 drops are added to the testing cylinder to produce a color change that can be graded using the Taylor K-2000 series comparator. This 1 ounce (30 mL) bottle contains enough R-0004 reagent for around 100 tests.
