Product Description
Milwaukee MI509-100 pH Reagent Kit (100 Tests)Measure water pH with speed and accuracy using the Milwaukee MI509-100 pH Reagent Kit — 100 pre-made phenol red liquid reagent tests formulated specifically for the Milwaukee MI411 Free & Total Chlorine & pH Photometer.The phenol red colorimetric method delivers fast, reliable pH readings across the critical 6.5–8.0 range — the most important pH window for pool safety, drinking water compliance, and aquatic system management. Simply add the reagent to your water sample, wait for the color reaction, and let the MI411 photometer determine the exact pH value.Key Features
100 Pre-Made Liquid Tests: Ready-to-use reagents — no preparation, no measuring errors, no dilution
Phenol Red Method: Proven colorimetric indicator for accurate pH measurement in the 6.5–8.0 range
pH Range: 6.5 – 8.0 pH units — covers the critical range for pool, drinking water, and aquatic applications
MI411-Specific Formulation: Calibrated to the Milwaukee MI411 photometer’s optical system for maximum accuracy
Expiration Date & Lot Number: Every test is marked for full traceability and quality assurance
Precision & Ease of Use: Add reagent, wait for color reaction, insert cuvette into MI411 — pH result in seconds
Why pH MatterspH is one of the most critical water quality parameters across virtually every water application. In swimming pools, pH outside the 7.2–7.8 range reduces chlorine effectiveness, causes swimmer irritation, and accelerates equipment corrosion. In drinking water, pH affects taste, pipe integrity, and disinfection efficiency. In aquaculture and aquariums, pH directly impacts fish health and biological filtration. The MI509-100 gives you fast, accurate pH data to keep your water in balance.How It WorksThe phenol red indicator changes color across the pH 6.5–8.0 range — from yellow at low pH to red/magenta at high pH. The MI411 photometer measures the color intensity photometrically and converts it to a precise pH reading, eliminating the subjectivity of visual color comparison strips.How to Use
Fill a clean cuvette with your water sample to the fill line
Add one MI509-100 reagent test to the cuvette
Cap and gently mix until the reagent is fully dissolved
Wait for the color reaction to develop (per MI411 instructions)
Wipe the outside of the cuvette and insert into the MI411 photometer
Select pH mode and read the result on the display
Compatible With
Photometer: Milwaukee MI411 Free & Total Chlorine & pH Photometer
Test Parameter: pH
pH Range: 6.5 – 8.0 pH units
Method: Phenol red colorimetric
Applications
Swimming pool and spa pH monitoring
Drinking water treatment pH compliance testing
Aquaculture and fish farm water quality
Aquarium and reef tank pH management
Recreational water facility management
Laboratory water quality analysis
Specifications
Model: MI509-100
Brand: Milwaukee Instruments
Test Parameter: pH
Testing Method: Phenol red colorimetric
pH Range: 6.5 – 8.0 pH units
Quantity: 100 liquid reagent tests
Compatible Meter: Milwaukee MI411 Photometer
MPN: MI509-100
UPC: 810666001010
Storage & HandlingStore in a cool, dry place away from direct sunlight and heat. Keep reagents sealed until ready to use. Do not use reagents that appear discolored or show signs of contamination. Always check the expiration date and lot number before use to ensure reagent integrity and measurement accuracy.Need chlorine testing too? See the Milwaukee MI511-100 — a complete Free Chlorine, Total Chlorine & pH reagent kit for the MI411 in a single package. Pair with Milwaukee MI0001 Glass Cuvettes for a complete photometric testing setup.
