Managing water balance and controlling organics

by jason_cramp | February 23, 2021 2:24 pm

By Kevin Vlietstra

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Whether one calls it winterizing, closing, off-season, or end-of-season pool care—how service professionals deal with pool water once there is not much pool activity all boils down to what part of the country the pool is located. In all cases, the two variables that need to be addressed are: a) managing water balance and, b) controlling organics.

This article will focus on the various products that can be used to balance pool water as well as the products that can be used to control organics during the winter months. The likelihood of a successful spring start-up will improve greatly when both are taken into consideration.

Water balance

Water balance factors include pH, total alkalinity (TA), calcium hardness (CH), water temperature, and total dissolved solids (TDS). During the season service professionals look to maintain these water balance levels to ‘ideal’ levels. In these ideal conditions, whether they are at the lower or upper end of the scale, the water is close to ‘balanced’ according to an equation that helps determine the potential for scaling. This equation is known as the Langelier Saturation Index (LSI) or saturation index.

[2]For example, in terms of in-season water temperature, most pools are kept around 27.7 C (82 F). As the peak pool season winds down, so do water temperatures. As the temperatures decrease so does the indicating number in the LSI. This value describes the water’s potential to be more corrosive or aggressive. The LSI chart on the opposite page (see Figure 1) shows how the number decreases as the water temperature declines whether the minimum or maximum ideal water care parameters are being used. Of course, many pools will not register right on the minimum and maximum of the index; the purpose is to demonstrate how important it is to adjust during the pool’s last days that it remains open. Inaction may cause one to have to react to a problem next season.

Regardless of geography, one of the ways service techs can move the needle on the LSI scale is by adding an all-purpose sequestering treatment product prior to closing the homeowner’s pool or by adding it continuously throughout the off-season. These treatments bond with soluble metals (such as calcium) to prevent the formation of scale.

Essentially, this maintenance routine moves the total LSI reading to a higher positive number. When traceable heavier metals are present, such as iron and copper, the use of all-purpose treatments will prevent these metals from creating stains and discolouring the water when the pool is not being used.

Algae

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The other element of seasonal pool maintenance has to do with what grows in the water. Mould, algae, bacteria, viruses, and other micro-organisms all linger in the pool regardless of the season. However, as the water temperature decreases, the activity of these issues also declines—sometimes exponentially. Just like when the pool is open, there is equal importance to eliminating water quality issues—or at least keeping them under control—while the pool is closed.

Using a product to keep algae growth under control is universal in the approach to off-season care. This is regardless if the homeowner covers the pool or leaves it exposed to the elements during the pool’s inactivity. That said, there are essentially three types of algaecides to consider.

Algaecide can utilize quaternary ammonium compounds (also often referred to as quat algaecides). They are inexpensive and have the potential of ridding the pool of existing algae. However, these algaecides, especially at higher concentrations, may cause foaming. Further, when chlorine is administered in the water at high levels, the effectiveness of quat-based algaecides is diminished.

Other algaecides include those that contain poly dimethyliminio ethanediyl dichloride. These algaecides are usually referred to as poly algaecides. They are non-foaming and offer greater staying power in the water in the presence
of chlorine.

Lastly, algaecides with the presence of copper are effective chemistries to combat algae in the long-term. These types of algae inhibitors are like poly algaecides as they are typically non-foaming and hold well in the water even in the presence of chlorine. Though these are the three basic types of algaecides used in pool winterization, there are plenty other variations/hybrids of these algaecides. Poly and copper hybrid algaecides are a growing market segment because they offer the advantages of two separate algaecides in a single container.

Shocking

When service techs close pools, shocking the water is a must to reduce the number of contaminants in the pool. After the water is shocked, contaminant loads are reduced which frees disinfectant (sanitizer) to help control the other materials lingering in the water—either currently or those introduced during the off-season. In this case, some service techs prefer to use chlorinated products, while others like to use non-chlorine oxidizing shocks.

There are advantages to using chlorinating products when closing a pool. For instance, if chlorine levels are non-existent, then applying a chlorinating shock will simultaneously scourer the pool of algae, bacteria, and other contaminants, while leaving a residual sanitizer for the period the pool is closed. When stabilized chlorines are used, the impact to the pH is also minimized.

Non-chlorine oxidizing shocks, relative to chlorine, is still an up and comer in the recreational water maintenance industry. Since most service professionals are comfortable with chlorine, many do not look at non-chlorine products as an effective tool—especially when it comes to winterizing. However, just because the product does not have chlorine present, it does not mean it is any less of an oxidizer. Non-chlorine oxidizers can scour more contaminants in the water than chlorine and, since it does not contain any chlorine itself, it will not form with chlorine to create any disinfection byproducts. Most importantly, its lack of chlorine is better for the long-term appearance of the pool’s surface. Regardless of its effectiveness as an oxidizer, a chlorine presence during the off-season is still a must.

Additional treatments

Depending on where the pool is located (in terms of geography), the quantity of products and the frequency of their application as part of a pool winterization program may vary. In Canada and the northern United States, service techs typically treat the pool once, as a cover is placed on the pool, which prevents outside debris and waste materials from falling into to the water. For those who do place covers on pools and experience mid-winter thaws, or those who have mesh-covers, additional algaecide treatments are important to keep growth under control.

In southern and southern-coastal communities, a cover is not typically placed on the pool. The lack of a cover means the pool water is exposed to outside debris and, of course, the sun. Due to the pool’s exposure to the elements, the water needs to be treated more often than a pool located in the north, but greatly less than in-season due to the colder weather.

Supplements

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Enzymatic treatments are a good option when closing pools for the season. The benefits many pool professionals tip their hats to when using these types of products is their ability to prevent a waterline ring from forming around the pool during the closing. While an important function, these chemistries will breakdown complicated structures in the water, allowing chlorine (and algaecides) to effectively do their jobs.

Borate based water treatments offer superior protection to surfaces as they inhibit corrosion and scale. Use of these products will not excuse one from having to balance the water initially. However, its use at closing time is an added insurance policy that the water balance will be identical from closing to open. This could be a great benefit for those pools with covers that allow rain and melted snow to enter the water. Borate’s natural clarifying ability can help maintain water clarity during the off-season as well.

Anywhere there is exposed water during off-season care, evaporation is likely to occur. Placing a solar cover on the water or using a specialty liquid formula that mimics a solar cover can help reduce evaporation. The benefit of either one (or both) will reduce the amount of time or at least the amount of water that will be needed to top off the pool.

Equipment

In Northern climates, it is likely for pools to experience prolonged freezing conditions. In these harsh settings, it is wise for pool professionals to vacate the water from everywhere but the pool itself. This includes the pump, filter, heater, skimmer, and effluent and influent line.

After evacuating the plumbing lines service technicians should use an anti-freeze solution in the skimmer and plumbing as it is a cheap insurance policy should water retreat into these areas. For even more protection, add a sacrificial plug to the skimmer in the event it becomes flooded with water.

In Northern areas, equipment plugs should be left removed and drained. Also, service technicians should consider removing pressure gauges and switches from the various components as they typically have a small amount of water remaining in them. If there is a multi-port valve attached in the equipment system it should be moved to the closed position, or at least in-between valve positions, so the gasket does not rest in one position throughout the off-season.

Other helpful winterizing devices include items such as snap-on skimmer closures that can eliminate costly water draining in the winter. These devices are easy to install and help protect the skimmer from freezing, while at the same time conserve valuable, treated pool water. In addition, many pool professionals use a specialized ‘blow out plug’ for pool winterization. This plug allows air and water to flow freely when pressure is applied and seals with an O-ring. It can even function as a hydrostatic relief valve or a multi-directional return fitting.

If the pool is not covered, as is the case with pools in more southern locations, the water must be circulated to maintain its appearance. Fortunately, since the activity both in and around the pool is significantly reduced, there is less contaminates in the pool and the growth of algae is slower; therefore, the water can be circulated less than it would be during the season. Circulation is going to be important to those who do not completely shut down the pool to avoid the plumbing and equipment from freezing. Pools can be equipped with ‘freeze-guards’ which will automatically turn on the pump in the event the water retreats to a certain temperature.

Conclusion

All pool professionals have their own method to closing pools. Some use anti-freeze, some do not. Some like adding chlorine, while others use non-chlorine alternatives. Some cover the pool when it is not necessary, while others do not. Regardless, of where, when, or how the pool is closed, the purpose of winterizing is to ensure that when the sun and hot weather returns, the customer’s pool is ready to be turned back on with minimal effort. Incorporating just a few of these recommendations as part of a service technician’s winterizing program could help reduce their efforts further during pool opening season.

[5]Kevin is the technical director and regulatory specialist with Haviland Pool and Spa Products. He has been working in the recreational water industry for more than 20 years. He can be reached via email at kevinv@havilandusa.com[6].

Source URL: https://www.poolspamarketing.com/trade/features/managing-water-balance-and-controlling-organics/

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