Active oxygen reagent tablets for pool photometer — 50 count

DPD N°4 Reagent Tablets (50) – for Pool Photometers

$13.99 $16.99
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Active oxygen reagent tablets for pool photometer — 50 count
  • Active oxygen reagent tablets for pool photometer — 50 count
  • PoolWaterLAB Free Chlorine reagent tablets (50) for pool photometer testing, close-up of tablets
DPD N°4 Reagent Tablets (50) – for Pool Photometers

DPD N°4 Reagent Tablets (50) – for Pool Photometers

Reagent · Tablet
$13.99 $16.99

Key facts

For: PoolWaterLAB V2.0

Listed shelf life: 2 years. Check the expiration date and storage instructions on the package.

See the product description for pack contents. Test counts depend on the selected method, its dose, and all required reagents.

Chemical reagents are excluded from voluntary change-of-mind returns. Damaged, defective, incorrect, or materially misdescribed items are handled separately. Read the refund policy.

Test method & instructions

View measured parameters and required supplies

Open the step-by-step testing instructions

 Choose the method that matches the parameter, reagent format, and measuring range. Follow that method's specified sample volume, ZERO procedure, reagent quantities, mixing, and reaction time. Some tests need additional reagents or accessories such as filters or a shaker. Use the Measured Parameters reference and the step-by-step instructions to check the complete procedure; do not assume every test uses one tablet or a 10 mL sample.

Description & how to use

Check the test method and required supplies

DPD N°4 Reagent Tablets (50) are photometer-compatible replacement / refill reagent tablets used for accurate pool & spa testing.

Key Specs

  • Product type: Replacement / refill reagent tablets (consumable)
  • Test parameter: Active oxygen
  • Format: Tablet reagent (50 tablets)
  • Shelf life: 2 years (sealed, stored properly)

What this reagent does

DPD N° 4 is a reagent used by compatible photometers to measure Active oxygen. Water disinfected with persulfate-containing media is measured according to the DPD N° 4 method.

Storage & shelf life

Store tablets cool, dry, and sealed. Avoid humidity and heat.

  • Recommended storage temperature: 59-77°F (15-25°C)
  • Protect from: moisture/water and direct heat

Proper storage helps maintain accuracy and supports the stated shelf life.

Material Safety Data Sheet (MSDS) — Download

Note: Product performance depends on correct testing procedure and proper tablet storage.

Shipping & returns

Shipping policy · Refund policy · Contact Us

Shipping

Free shipping on U.S. orders over $100. Orders are shipped within 24 hours. Worldwide delivery costs are calculated at checkout. See the shipping policy for full details.

Reagent returns

Chemical reagents are excluded from voluntary change-of-mind returns and exchanges because their storage and handling conditions cannot be verified after delivery. If an item arrives damaged, defective, incorrect, or materially not as described, contact info@poolwaterlab.us promptly. Do not send reagents back without receiving instructions. These exclusions do not limit remedies required by applicable law. Read the full refund policy for details.

Match the reagent to the right test

Use the exact reagent format, range, sample volume, dose, and preparation steps specified for your method. The reference library lists the reagents and accessories each test needs.
View measured parameters Download MSDS (PDF)

How testing works · Reagent cost per test · Saltwater compatibility

Explore the PoolWaterLAB Photometer V2.0

Complete your test setup

Additional items for the primary test method linked to this reagent. Check the method instructions for the complete reagent and accessory list.

Frequently asked questions

What reagents are compatible with PoolWaterLAB?
PoolWaterLAB is designed to work with official PoolWaterLAB reagents developed for its supported test methods. Using official PoolWaterLAB reagents helps ensure accurate, repeatable, and reliable water test results.

Compatibility and test methods
How do I choose the correct test method?

Choose the method that matches the parameter, reagent format, and measuring range. Follow that method's specified sample volume, ZERO procedure, reagent quantities, mixing, and reaction time. Some tests need additional reagents or accessories such as filters or a shaker. Use the Measured Parameters reference and the step-by-step instructions to check the complete procedure; do not assume every test uses one tablet or a 10 mL sample.

Method instructions
How many tests can I perform with one package of PoolWaterLAB reagents?

The number of complete tests depends on the product, the selected method, and the quantity of each required reagent. A tablet or powder-pillow count is not automatically the number of complete tests: some procedures use multiple reagents or more than one dose. Check the product description, package contents, and method instructions for the required sample volume, dose, and reaction time.

Reagent cost per test
How should I store PoolWaterLAB reagents?

Store PoolWaterLAB reagents in a cool, dry place away from direct sunlight, excessive heat, and moisture. Keep containers tightly closed and always follow the storage instructions provided on the product packaging. Proper storage helps maintain reagent performance and ensures accurate water test results.
Can I use it in a saltwater pool?

Yes, for the tests listed as compatible with saltwater. Suitability depends on the parameter and salt concentration; not every method is suitable for seawater. Check the saltwater compatibility table and pH notes before testing.

Saltwater compatibility
Can I return chemical reagents?

Chemical reagents are excluded from voluntary change-of-mind returns and exchanges because their storage and handling conditions cannot be verified after delivery. If an item arrives damaged, defective, incorrect, or materially not as described, contact info@poolwaterlab.us promptly. Do not send reagents back without receiving instructions. These exclusions do not limit remedies required by applicable law. Read the full refund policy for details.

Refund policy

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