FAQ

One of the benefits of test strips is their convenience – you can dip directly into a pool or spa. You only need to dip the test strip deep enough to submerge all of the test pads. Do not swish, scoop or shake the test strip. Simply dip in the water to get the pads wet & remove.

If you still prefer to use a sample cup, be sure it has been rinsed and is free of any residue as it could affect test results – particularly chlorine. Since it is such a small volume of water, do not dip more than one test strip in the water sample as it could impact subsequent tests.

Almost all chemical analyses complete at a specified time; if you read it too early the chemical reaction may not be complete or if you wait too long, the chemical reaction will continue to evolve. For reagent test pads, follow the read times on the color card to get the best possible results.

Are there interferences with this test if the chlorine level is very high (above 20ppm)?

Unlike liquid or tablet kits, the DPD Pro test strip pads that detect free and total chlorine do not bleach out even at levels greater than 100ppm (though a pool or spa should never get this high). But if the chlorine level is very high (above 20ppm) you may observe lighter shadows or “window framing” on the pH pad. If this occurs, wait for the chlorine level to drop to 20ppm or lower, and retest the pH.

Having Total Chlorine and Free Chlorine readings simultaneously makes it easy to quickly identify whether combined chlorine is present. Simply take the Total Chlorine (TC) ppm reading and subtract the Free Chlorine ppm reading (FC) to determine combined chlorine (CC). TC – FC = CC.

Most of the hardness in pool and spa water can be attributed to calcium, though the DPD ProTM Total Hardness will detect the total amount of Calcium and Magnesium.

Refill bottles are available for both test strip configurations:

  • 3-way Total Chlorine/Free Chlorine/pH test strip refills part#562701 for a 6 pack of bottles  
    * the color chart comes with the test kit only
  • 4-way Low Range Total Hardness/High Range Total Hardness/Cyanuric Acid/Total Alkalinity test strip refills part# 562801 for a 6 pack of bottles
    * the color chart comes with the test kit only

An expiration date is printed on each test strip bottle label; you should not use the strips past that date. If the test strips have not been stored according to label directions (cap on tight, room temperature) they may no longer be good even if they are not expired. Or if the public pool in your facility is seasonal or closed for a period of time, consider replacing with fresh strips.

Please email us at dpdpro@hach.com to order a replacement color card.

It meets state and country regulations that require the use of N,N-Diethyl-p-Phenylenediamine (DPD) for detecting free and total chlorine as well as regulations that require the use of phenol red for pH.

Yes. Test strips were developed for the medical diagnostic industry in the 1960s. Since then, they have replaced liquid reagent tests for urine and blood testing. DPD Pro Test Strips use this same, trusted technology to provide accurate results regarding water quality.

Test strips offer comparable accuracy to liquid color comparator tests. You may find that results are even more accurate because liquid kits require measuring samples and counting drops of reagent, which allows for a higher margin of human error. If you are interested in learning more consider downloading the whitepaper on this site.

Store your test kit in a cool, dry place and avoid touching the test strip pads prior to testing, as this could affect results. It is important to keep the lids of pool/spa test strips bottles securely tightened when not in use and not to remove the desiccants (moisture protection pillow) in the test strip bottle.

Target ranges for sanitizer levels, pH, etc. vary from county to county and state from sate. Furthermore, ideal levels for these same parameters can vary based on the type of pool, spa or water feature as well. Refer to state or local regulations to determine if your test results are within the recommended guidelines.

Should a result be observed where the coloration of the pad is not uniform, the reading should be interpreted and compared to the color chart using the darkest portion of the test pad.

One of the benefits of test strips is their convenience – you can dip directly into a pool or spa. You only need to dip the test strip deep enough to submerge all of the test pads. Do not swish, scoop or shake the test strip. Simply dip in the water to get the pads wet & remove.

If you still prefer to use a sample cup, be sure it has been rinsed and is free of any residue as it could affect test results – particularly chlorine. Since it is such a small volume of water, do not dip more than one test strip in the water sample as it could impact subsequent tests.

Almost all chemical analyses complete at a specified time; if you read it too early the chemical reaction may not be complete or if you wait too long, the chemical reaction will continue to evolve. For reagent test pads, follow the read times on the color card to get the best possible results.

Unlike liquid or tablet kits, the DPD Pro test strip pads that detect free and total chlorine do not bleach out even at levels greater than 100ppm (though a pool or spa should never get this high). But if the chlorine level is very high (above 20ppm) you may observe lighter shadows or “window framing” on the pH pad. If this occurs, wait for the chlorine level to drop to 20ppm or lower, and retest the pH.

Please email us at dpdpro@hach.com to order a replacement color card.

It meets state and country regulations that require the use of N,N-Diethyl-p-Phenylenediamine (DPD) for detecting free and total chlorine as well as regulations that require the use of phenol red for pH.

Yes. Test strips were developed for the medical diagnostic industry in the 1960s. Since then, they have replaced liquid reagent tests for urine and blood testing. DPD Pro Test Strips use this same, trusted technology to provide accurate results regarding water quality.

Test strips offer comparable accuracy to liquid color comparator tests. You may find that results are even more accurate because liquid kits require measuring samples and counting drops of reagent, which allows for a higher margin of human error. If you are interested in learning more consider downloading the whitepaper on this site.

Refill bottles are available for both test strip configurations:

  • 3-way Total Chlorine/Free Chlorine/pH test strip refills part#562701 for a 6 pack of bottles
    * the color chart comes with the test kit only
  • 4-way Low Range Total Hardness/High Range Total Hardness/Cyanuric Acid/Total Alkalinity test strip refills part# 562801 for a 6 pack of bottles
    * the color chart comes with the test kit only

An expiration date is printed on each test strip bottle label; you should not use the strips past that date. If the test strips have not been stored according to label directions (cap on tight, room temperature) they may no longer be good even if they are not expired. Or if the public pool in your facility is seasonal or closed for a period of time, consider replacing with fresh strips.