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LaMotte Spin Touch vs Non-Digital Testing

Pool water testing is a vital process when it comes to keeping pools functioning and safe.

Testing is not only smart and responsible, but is also required by state health departments. Something pool operators must keep in mind is that the type of testing kit used can make a significant difference in testing results and ease of pool maintenance, and is therefore a decision with serious consequences. 

The LaMotte Spin Touch can outperform non-digital testing methods in almost every way.

By far the most important metric to measure different testing methods by is accuracy, as the accuracy of pool water testing can dramatically affect the condition and chemical balance of pools. The chemical balance or imbalance of pools is crucial to be aware of, as it can end up either costing or saving pool operators thousands of dollars.

While some experienced users and experts can achieve the stated accuracy of non-digital testing methods like strip or liquid test kits, most users can’t. Particularly when using liquid testing kits, this is due to the many different user errors that can lead to inaccurate testing results, including not filling the test tube with the proper amount of water, contaminating the testing samples and misinterpreting the sample results. Even within the scope of these testing errors, there are many user mistakes that can lead to each one.

Users failing to get accurate test results using pool testing drops can occur due to:

  • Failing to hold the reagent bottle vertically when dropping reagent into the pool water sample, meaning drops of reagent aren’t always consistent sizes
  • Miscounting drops due to distractions or negligence 
  • Using expired reagents for testing

The LaMotte Spin Touch can minimize the risk of these mistakes as it is far easier to fill.

Users simply need to take a syringe of pool water and inject it into a testing disk so that there are no air bubbles, then insert the disk into the machine. There is no error due to adding the wrong amount of reagent because the user isn’t required to do so, and as long as they inject the proper amount of pool water into the testing disk, testing should occur with little error.

Users contaminating samples using non-digital pool test kits can occur due to:

  • Failing to wash test tubes properly between tests
  • Users using their thumb instead of a clean cover to seal the end of the test tube when inverting the sample

The LaMotte Spin Touch minimizes the risk that samples are contaminated by using a new disk with each test, ensuring that the disk is clean and won’t contain residue from previous tests.

Users misinterpreting pool test sample colors can occur due to:

  • Different users seeing the same colors differently
  • Improper lighting leading to a change in the appearance of the color (many liquid testing kits are intended for outside use)
  • Different backdrops making colors appear differently, especially darker backdrops

The error due to color misinterpretation doesn’t come into play when using The LaMotte Spin Touch, as users aren’t required to interpret the coloration of tested pool water. Spin touch automates the testing process in a consistent, controlled internal environment.

Testing standards that pool water testers are rated on are classified by NSF International, which bases these ratings on their testing accuracy from L1 level (most accurate) to L3 level (least accurate), with testers below L3 not receiving a rating. The LaMotte Spin Touch is rated at L1 level, while most non-digital water testing methods aren’t rated, and the highest rated non-digital testers are visual liquid testers, which are rated L3 level. The following is a chart of the accuracy from level L1 to L3 when measuring Chlorine levels.

 

NSF L1, L2 and L3 Pool Water Testing Kit Accuracy for Chlorine

L1

Between 0 and 3

±0.2 ppm

 

Between 3 and 7

±0.7 ppm

 

Between 7 and 10

±1.5 ppm

     

L2

Between 0 and 1

±0.25 ppm

 

Between 1 and 3

±0.5 ppm

 

Between 3 and 5

±1.0 ppm

 

Between 5 and 10

±2.5 ppm

     

L3

Between 0 and 1

±0.25 ppm

 

Between 1 and 3

±0.5 ppm

 

Between 3 and 5

±1.0 ppm

 

Between 5 and 10

±2.5 ppm

 

Strip or comparator

Within 1 increment of expected value

 

The Consequences of Bad Pool Water Testing

The consequences of bad, inaccurate testing can be severe. In the best case scenario, managers will occasionally add too many chemicals when their addition isn’t necessary. Inaccurate tests can sometimes indicate that chemical balance appears to be off when it isn’t, and vice versa. Chemical correction via addition when it is unnecessary can waste expensive chemicals, throwing a pool that was previously chemically balanced out of balance. On the other hand, a lack of correction when it is necessary can allow a pool to fall out of balance. This is especially critical in facilities only testing water chemicals once daily, as chemical levels can fluctuate dramatically in 24 hours based on over or under-correction. 

Worst case scenario, inaccurate testing can allow pools to become severely unbalanced. This can lead to pools going cloudy and/or green, requiring the pool to be shut down while expensive chemicals are added to clear up the water or until outside professional help can arrive. Worse yet, inaccurate testing, especially in hot tubs, can lead to health risks like Legionnaires Disease. Sicknesses from an improperly maintained pool or hot tub can end with lawsuits against pool owners and operators and pools or hot tubs being shut down by the local health department.

Real World LaMotte Spin Touch vs Pool Color Strip Testing Example

To give an example of how testing accuracy can affect operation, here’s a real world scenario. Let’s say our CPO is testing a 100,000 Gallon lap pool at a hotel. The actual water chemical levels are as stated below, Free Chlorine 2.0 ppm and PH 7.4, which is in the ideal range for a pool. This table shows the variation that can occur for this amount of Chlorine and level of pH for testing kits of each testing level.

 

Chemical

Actual Amount

L1

L2

L3

Free Chlorine

2.0

1.8 - 2.2 ppm

1.5 - 2.5 ppm

1.5 - 2.5 ppm

pH

7.4

7.2 - 7.6

7.0 - 7.8

6.9 - 7.9

Using a NSF/ANSI 50 Certified device with an L1 rating like the LaMotte Spin Touch, the water test result shows Free Chlorine at 1.8 ppm and pH at 7.2. Both of these are acceptable and most likely no chemicals would be added to the pool. If the device erred on the high side with Free Chlorine at 2.2 ppm and pH at 7.6, they are again acceptable.

Using a NSF/ANSI 50 Certified device with an L3 rating like some drop kits results in a different, much more expensive outcome.

The Free Chlorine test may show levels at 1.5 ppm which is still in the acceptable range. Depending on the facility and pool usage, the CPO may add chlorine to raise the levels to 2.0 ppm as the levels are close to the facility designated lower limit of acceptance. It would take 53oz of 12.5% sodium hypochlorite to bring the chlorine to 2.0 ppm. Since the actual chlorine level is actually 2.0 ppm, they are using chemicals not really needed at the time.

The pH test shows a level of 6.9 which is outside the health department and Model Aquatic Health Code guidelines and requires 9.4 lbs amount of Sodium Carbonate to raise the level to 7.4.

If this test kit and user erred on the high side, the Free Chlorine test would show 2.5 ppm and pH at 7.9. The Free Chlorine would be within the range even though they would have less than what is actually in the pool to keep the water clean. pH would now be on the high side and may prompt the user to add 1.08 gallons of muriatic acid to bring it down to 7.4. (The muriatic acid would bring the actual pH down to 6.9 which would most likely require raising the pH after the next test.)

This example uses both the high and low acceptable ranges, and when you factor in the potential user errors that can occur with drop type tests like not holding the reagent bottle vertically, not making sure the test tube vials are clean and contaminating the sample by using a finger to keep the water in as you invert the water sample to mix the reagent, it becomes easier to hit these extremes.

Digital Pool Testers

Not all digital testing options are created equal, and there are many to choose from on the market. Most digital testers can only test one pool chemical or condition at a time, which can make the process of testing and corrections a time consuming process, especially when testing multiple metrics. Luckily, the LaMotte Spin Touch can test ten pool chemicals at a time, and can perform these tests in under a minute. This time savings can add up and have a substantial positive impact when testing multiple times a day. While any digital tester is an accuracy upgrade over non-digital options, the LaMotte Spin Touch is a cut above in terms of ease of use and speed.

 

Digital Pool Tester Guide

The benefits of implementing Pool Shark include:

  • Substantial ROI
  • Better Water Conditions
  • Improved Guest & Customer Satisfaction
  • Plug and Play Ease of Use
  • Stronger Risk Management & Reduced Liability
  • Guides and Practices
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