Product Information
Description
LaMotte P-6741-H DPD 1B Free Chlorine Liquid Reagent, 60 mL
Accurate free chlorine, drop by drop.
The LaMotte DPD 1B Liquid Reagent (MPN P-6741-H, SKU PST-P6741H) is the buffer half of LaMotte's two-part liquid DPD system for measuring free available chlorine in pool, spa, drinking water, and industrial water samples. Paired with DPD 1A (P-6740-H), it develops a clean pink color that reads accurately on LaMotte chlorine comparators and colorimeters. Use it as a direct liquid alternative to DPD tablets in your existing LaMotte test kit.
Why PST Customers Pick This
Free Chlorine Accuracy
Used with DPD 1A to develop the pink color that LaMotte comparators and colorimeters read for free available chlorine, the chlorine that actually sanitizes your pool or spa.
Liquid Format
A drop-in liquid alternative to DPD tablets. No crushing, no powder residue, no slow dissolve, just count drops and read the color.
Two-Part System
Designed to be used with DPD 1A (P-6740-H). Both reagents are added to a 5 or 10 mL water sample before reading.
Comparator and Colorimeter Ready
Works with LaMotte ColorQ, Smart3, and traditional octa-slide chlorine comparators that call for liquid DPD reagents.
Pool, Spa, and More
Validated for pool and spa water, drinking water, food and beverage, cooling and boiler water, laundry, and wastewater sanitation testing.
60 mL Refill Bottle
The 60 mL size delivers roughly 288 tests, enough for a full season of weekly testing or a busy service route's monthly restock.
Handling Notice
DPD 1B is a laboratory reagent. Keep the bottle tightly capped, stored cool and dry, and away from direct sunlight to preserve accuracy. Avoid skin and eye contact, wash hands after testing, and keep out of reach of children. This reagent ships ground only, it cannot ship by air.
Specifications
Frequently Asked Questions
What is the difference between DPD 1A and DPD 1B?
Both are part of the same free chlorine test. DPD 1A (P-6740-H) contains the indicator that reacts with free chlorine to produce a pink color, and DPD 1B (P-6741-H) is the buffer that holds the sample at the correct pH so the color develops accurately. You need both bottles for a free chlorine reading.
Which LaMotte test kits use this reagent?
P-6741-H is the refill bottle for any LaMotte kit that calls for liquid DPD reagents, including the ColorQ Pro series, Smart3 photometer kits, and the traditional octa-slide chlorine comparators. Check the reagent list inside your kit lid, if it lists DPD 1B, this is the bottle.
How many tests do I get from one 60 mL bottle?
About 288 tests at the standard dosing of 5 drops per sample. Heavier dosing for higher-range readings will shorten the bottle life, and partial drops or spillage will too. For most residential pool owners, one bottle covers a full season.
Can I use this on a spa, hot tub, or drinking water?
Yes. The DPD method is the same chemistry used for residential pools, commercial spas, drinking water, cooling towers, and food and beverage sanitation. The reading range is set by your meter or comparator, not the reagent.
How should I store the reagent and how long does it last?
Store the bottle tightly capped, upright, cool, dry, and out of direct sunlight. LaMotte guarantees a minimum 6 months of shelf life at shipment, with a typical shelf life of 12 months from manufacture. Replace the bottle if the liquid turns cloudy, discolored, or fails to develop color on a known chlorine standard.
Order LaMotte P-6741-H From PST
Authorized LaMotte dealer with fresh DPD 1B liquid reagent in stock and ready to ship ground.
Additional Info
| Category | Pool Products Pool Testing Supplies Replacement Reagents |
| SKU | PST-P6741H |
| MPN | P-6741-H |
| Manufacturer | Lamotte |
| Weight | 0.0 lb |
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