Testing water integrity: It is all about having the right information

by brittney_cutler_2 | October 24, 2021 8:00 am

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By Des Caruana

Pool installations are becoming more complex by the day; commercial and residential modern day mechanical equipment can make even a seasoned operator a little apprehensive. Chemical controllers, filters, heaters, and even lights can now all be monitored and operated from halfway across the world. When looking at all the technology, filters with touch screens, and chemical controllers lighting up in different colours, one must remind themself of this simple principle: a pool is a shell that needs to have balanced water.

Water must get from the shell into the mechanical room by way of a pump or, in some cases, several pumps. The water needs to get filtered, heated, chemically treated, and then returned to the pool shell. In many installations, there is also the addition of ultraviolet (UV) and ozone.

Operators should never underestimate the importance of a person performing daily mechanical room observations or preventative and daily maintenance as technology does not eliminate the importance of water testing and water balancing. As complicated and complex as these pools and mechanical systems can get, one must always remember to keep things simple.

What’s in my water-source water testing?

It is important to test the source water before a new pool’s first fill, although it is often an afterthought after the initial fill. It is critical to know what the readings are of the source water to have the appropriate chemicals on hand to treat the water immediately after the initial fill. This saves valuable time and prevents potentially aggressive water from staining a new pool finish.

Many commercial and residential applications can have the source water go through a water softener before getting added to the pool. For example, on a recently finished high school pool project with a water volume of 1,854,852 L (490,000 gal), when testing the source water before filling, the calcium hardness was found to be 150 parts per million (ppm). Knowing this information, it was determined 353 kg (778 lbs) of 85 per cent calcium chloride (CaCl) had to be added to the water on the initial fill.

Having this water quality information is valuable because it can also be used to calculate an estimate of how much the owner will need on hand for a 30-day supply. In this case, the source water also indicated higher levels of copper and iron; therefore, a sequestering product was also added to the initial fill. By knowing the makeup of the source water, the operators now know when making their monthly chemical orders they should get slightly more calcium chloride as well as have a sequestering product on hand. Every pool will need fresh water added daily. It can be from a sophisticated water system controlled by sensors to add the water in automatically or from a simple garden hose.

Whichever way the fill water is added, it is better to be prepared by knowing what is in the water. It is a good idea to test the source water at a minimum once a month, more if possible. Municipal water can change and understanding even minimal changes can help operators determine what needs to be added to a pool to balance the water chemistry.

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Testing methods

There are many water test kits on the market. Electronic test kits are beneficial as they can test a wide variety of parameters including salt levels, copper, iron, and phosphates. The only issue with some of the electronic test kits can be the price. These devices can stretch the budget and are not the most cost-effective method for testing only one body of water. It is also important to keep in mind to never freeze reagents and watch the expiry dates. Yes—reagents expire.

Some test kits on the market come with everything needed: a cyanuric acid (CYA) stabilizer test for outdoor pools, Langelier Saturation Index (LSI) calculator, and a handy book on what chemicals to use and how much to use to balance water. Many pool operators will take a test sample of the water and source water to a local service company to have them test the extra parameters the kit does not include. There are also inexpensive test strips for phosphates and metallics.

However, testing water manually is the best way to stay on top of things. Regardless of how busy one is, it is important to never skip a test and just copy the last test results in the logbook. It can be a dangerous practice. Even with a reliable state-of-the-art chemical controller, electronics can fail and should never replace manual water testing.

One very important device often missing is a total dissolved solids (TDS) meter. It is crucial to know the amount of TDS in the water; this information goes a long way to having pristine balanced water. The great thing about TDS is not needing any expensive chemicals to get reduce the amount in the water. Once it reaches 2000 ppm, approximately 152 mm (6 in.) of water should be drained from the pool and then topped back up. Upon topping the water up, there is no surprise with other level changes from adding all that fresh water.

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Is this water balanced?

A mentor used to ask the question: “How do you know your water is balanced?” He often received an assortment of answers. The only way to know the pool water is balanced is by using the LSI, though on many sites the LSI wheel is often found in its original packaging and had never been used.

The LSI helps keep water silky smooth and safe for all swimmers and it keeps things very simple. The LSI calculates pH, total alkalinity, calcium hardness, and temperature. Keeping TDS below 2000 ppm is also a big part of water balance. One analogy to use when training operators is to tell them to treat it like a game. The object of the game is to score zero with a range of -0.3 and +0.5. The negative side equals aggressive corrosive water, while the positive side equals scale deposits and cloudy water. The best way to keeping water balanced is to have a goal, something to aim for: 0.0 on the LSI scale.

After chemical checks and plotting results using the LSI calculator, one can see the quality of the water. If the water falls above or below zero, an operator is now more prepared to make the necessary adjustments to get the score back to zero without aimlessly adding chemicals to a pool before having all the information. Operators often say they used less chemicals than before, keeping their water always as close to zero as possible prevents the water balance fluctuations.

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It does not take long for a pool on the negative side of the LSI to have adverse, irreversible, and expensive damage done. For example, in one pool that was under two years old, the calcium hardness and alkalinity were kept extremely low. The pool water was corrosive, and, in just two years, the surface was permanently stained and damaged. There is also brown staining on the pool’s gutter system..

Bathers complained the water was uncomfortable to swim in and they could not stay in the water for long periods. This corrosive water will cause stainless steel to rust, heat exchangers and pumps to corrode, resulting in copper leaking into the water. Further, due to the acidic nature of the water, the plaster was etched and became rough. This example is extreme, but it unfortunately happens often. It is a condition that is avoidable with the proper knowledge of pool chemistry and by using the simple tools available.

Des Caruana has an extensive and vast background in the pool industry. With more than 20 years of experience in construction, service, and tech. He spends his time travelling North America commissioning most of Acapulco Pools/Gall Construction along with performing operator training. Caruana also spends a great deal of time performing technical support for new and existing customers. He can be reached via email at des@acapulcopools.com.

Source URL: https://www.poolspamarketing.com/trade/features/testing-water-integrity-it-is-all-about-having-the-right-information/

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