Should you be using pool test strips or liquid test kits to measure your pool water chemistry?
It’s no secret the average pool owners prefer using test strips, while a minority prefer liquid test kits – but this article will explore what separates the two, and which one you should be using.
Quick answer: Pool test strips are cheaper, easier, and faster to use, but liquid drop test kits are considerably more accurate, broader in terms of their testing capabilities, and they tend to last longer than strips.
What Are Test Strips?
Pool test strips, also called ‘dip strips’, are little strips of paper with color-changing squares, which are activated by briefly dunking the strip into your pool.
They first became available in the 1960s for use in the medical industry but were soon marketed to and popularized by pool owners.
Before long, “5-way” and 7-way” strips were developed to test for a wider range of parameters in swimming pools, including markers like free chlorine, total hardness, cyanuric acid, and more.
What Are Liquid Test Kits?
Liquid test kits, also referred to as ‘liquid drop kits’, are plastic containers with liquid reagents to change the color of your sample water.
Taylor Technologies was a leader in marketing liquid test kits to the pool industry in the late 1960s, though reagents were used for various water testing purposes for many years prior.
Today, several other companies have joined Taylor in offering comprehensive liquid testing kits for pools, each with varying types of reagents to accommodate a broad range of chemical and mineral tests.
Test Strips vs Liquid Test Kits (Comparison)
Below are all the arguments for using one type of test kit over the other, along with a summary of each:
Test Strips Are Cheaper
Test strips are always going to be cheaper than liquid test kits.
For example, you can expect to buy a pack of 100 AquaChek strips for somewhere between $15 and $20.
Those strips would last you roughly 6 to 12 months depending on how frequently you’re testing your water, which means you’re looking at a fixed cost of between $15 and $40 per year.
Comparatively, the popular Taylor K-2006C liquid test kit will set you back around $130 with all the necessary reagents included (2oz bottles).
The supplied reagents would typically last you 12 months under reasonable usage, after which time you’ll need to refill the entire set for a total cost of around $50 to $70 per year.
To summarize:
- Test strips will cost you up to $40 per year.
- A liquid test kit will cost around $130 for the first year, and roughly half that amount for each year thereafter.
Test Strips Are Faster to Use
A test strip can be taken directly from the bottle, dipped into your pool for a few seconds, and then left on a flat surface for a few more seconds before showing results.
This whole process can be completed in less than a minute; a far cry from the time required to perform a drop test.
A liquid test kit can often take up several minutes in preparation alone, as it involves cleaning the container, taking a good water sample, identifying the correct reagent to use, and ensuring the right number of drops are added.
What’s more, you have to go through this process for each individual parameter, such as testing for pH, free chlorine, total chlorine, etc.
To summarize:
- A test strip will allow you to test for all supported parameters in under a minute.
- A liquid drop kit requires at least that amount of time to test a single parameter.
Test Strips Are Easier to Use
A test strip works standalone straight from the bottle, meaning it requires no reagents in order to give a reading.
All it needs is a brief exposure to water, and this makes the product far less prone to user error (something that happens more often in testing than you probably think).
Comparatively, liquid test kits are more complicated to use – even if they’re not nearly as complicated as they first appear.
The biggest issue in terms of ease of use is around using the reagents. Using anything but the required number of drops for each test will render the result invalid, forcing you to start over.
To summarize:
- Test strips only need to be dunked into the water once in order to provide a reading.
- Liquid test kits require a precise number of drops for each parameter using various reagents.
Liquid Test Kits Are More Accurate
Liquid test kits use “titration” to measure the chemical markers in the water, which simply means adding a reagent (titrant) to color a water sample.
This is a more accurate and more precise method of testing compared to test strips, although even liquid titration kits vary in accuracy depending on the type – such as OTO, DPD or FAS-DPD.
In comparison, test strips are sometimes referred to as “guess strips” due to the inconsistencies seen from one test to the next, especially when it comes to testing for cyanuric acid.
Much of this unreliability stems from how easily strips are compromised due to humidity in the air, but also how difficult it is to interpret the provided color chart as the colors on the strip will slowly change over time.
So, while test strips are cheaper initially, many experienced pool owners will argue the inaccuracy of results and subsequent false corrections far outweighs any savings you gain from using strips.
To summarize:
- Liquid test kits are based on titration; a more accurate and precise method of water testing.
- Test strips are more easily compromised and their results harder to interpret.
Liquid Kits Test for Other Parameters
Liquid testing kits allow for a wider range of tests and ultimately give you a more complete picture of your water chemistry.
While the parameters you can test for depends on the type of kit you own, test strips will always be limited in comparison.
For example, test strips can’t perform an acid demand test. They’re also only able to measure total hardness, which is calcium and magnesium together, as opposed to calcium alone in the form of a calcium hardness reading.
Considering the importance of calcium and saturation for maintaining plaster pools and preventing etching or scaling, this is one parameter many inground pool owners simply can’t afford to overlook.
Note: If you’re testing for borates or salt, an accurate or precise reading isn’t nearly as important which makes specialized test strips more viable for these particular parameters.
To summarize:
- Liquid test kits can test for a wider range of chemical or mineral concentrations based on the reagents you own.
- Test strips are always limited by what’s on the strip, and all are unable to test for acid/base demand or calcium hardness.
Liquid Test Kits Last a Long Time
Liquid test kits come complete with a set of reagents necessary to perform the various water tests.
The reagents last between a year and two years before they’re considered unreliable. Unfortunately, it’s not easy to tell efficacy just by looking at the liquid, which is why reagent expiry dates should be respected.
The kit container itself (the thing you use to perform the tests) can last many years with proper care, which means it’s often only the reagents that need replacing.
Strips, on the other hand, typically last up to a year at most. Once expired, they’re no longer reliable and the entire pack should be replaced.
In summary:
- Liquid test kits will last many years with refills required as little as every two years.
- Test trips will last up to a year after which point all strips should be replaced with a new pack.
Both Methods Have Their Place
If you have to choose between test strips or liquid test kits, it’s hard to argue with the accuracy of liquid test kits despite their slightly higher price point and time commitment.
With that being said, pool test strips are cheap, fast, and easy to use, which makes them ideal for more frequent testing of your water, whether it’s once a day or multiple times a day.
Finally, if cost isn’t a concern, you can get the best of both worlds by supplementing weekly or twice-weekly liquid tests with daily test strips.
