Protecting Your Pool Investment: Why Chemical Balance Before Closing Is Your Pool’s Winter Survival Strategy

As Long Island temperatures begin their inevitable autumn descent, pool owners face a critical decision point that could mean the difference between a smooth spring opening and thousands of dollars in damage. The secret lies not just in covering your pool, but in achieving the perfect chemical balance before winter’s harsh grip takes hold.

The Science Behind Winter Water Chemistry

A variety of nasty issues can plague your pool if the pool water isn’t properly balanced before winter arrives. With the right balance of chemicals in your pool water, you’re effectively protecting your investment before problems begin. When your pool sits dormant for months, your pool water isn’t being circulated so the chemicals cannot be evenly distributed throughout your pool. This makes pre-winterization chemical balance absolutely crucial.

Low calcium levels in a gunite pool can damage the plaster and cause etching on the surface of your pool. Low levels of calcium can also destroy vinyl pool liners. Low pH levels lead to surface corrosion on gunite pools and wrinkling in vinyl liner pools. These issues don’t develop overnight – they’re the result of months of chemical imbalance during the closed season.

Essential Chemical Parameters for Long Island Pools

pH Levels: Planning for Natural Decline

During the summer, swimming pools traditionally have a pH balance between 7.2 and 7.6. During the winter, it’s recommended that the pH be raised to 7.8. Over the days and weeks that your pool is closed, your pool’s pH will naturally lower itself. By raising the pH levels before pool closure, you’re offsetting the natural pH decrease that occurs over winter.

We raise the pH level because in stagnant water, pH will naturally lower itself over extended periods of time, such as when your pool is closed. Low pH levels can damage your pool surfaces or your liner, resulting in staining, and have other negative effects on your pool. By bringing the pH level to higher than normal levels, we offset the natural pH decrease that happens over the winter. If we keep our pH at 7.6 when we close the pool, the pH level would dip well below the minimum threshold of 7.4 within a month or two…with five months still to go before opening again.

Alkalinity: Your pH Buffer System

During the summer months, the optimum alkalinity range is between 120 – 140 ppm. This range is adequate because we are constantly monitoring our pool’s alkalinity and adding the appropriate chemicals as necessary. However, during the winter, we want to increase alkalinity so it’s in the 150 – 175 ppm range.

High alkalinity levels mean having to deal with cloudy pool water in the spring and make it that much more difficult to clear the water. However, the winter increase is necessary because alkalinity levels tend to decrease in stagnant water over long periods of time.

Calcium Hardness: Preventing Surface Damage

Unlike your pH and alkalinity, your calcium levels won’t decrease as the fall and winter months pass. But it’s still a good idea to ensure that its levels are adequate to prevent any unwelcome surprises once spring rolls around. Generally raising your calcium hardness levels to above 200ppm is all that’s necessary to prevent calcium from eroding your pool.

For pools that may experience freezing temperatures, if your pool will freeze, you will need a minimum of 400 ppm calcium hardness, but we recommend closer to 500 ppm. We increase the calcium level because your concrete pool relies on it to prevent erosion and weakening of your pool’s coating and of the concrete itself. Calcium is a physical part of water chemistry so it will not fluctuate over time, even after their preliminary water tests during the summer (which is why many pool owners forget to monitor it during the swimming season). However, by ensuring it’s at an adequate level when you close your pool, you’ll be doing a lot to prevent any unwelcome surprises in the spring that can lead to expensive repairs.

The Critical Timing Factor

This process should be started about one week prior to closing your pool. About five days before you plan to close the pool for the winter, follow these steps: Adjust the pH to a level between 7.2 and 7.8. Adjust the alkalinity to 80 to 120 ppm. Adjust the calcium hardness to 200 to 400 ppm.

We should always pre-dissolve and circulate dry chemicals when the water is still warm enough to do so. If you need to add calcium or bicarb to prepare your water’s LSI for pool winterization, do so weeks before closing when the water is warmer.

Sanitization and Algae Prevention

Several days prior to closing your pool, add a shock product to your pool water to kill any existing algae and bacteria. Before you shut things down for the season, it’s a good idea to hit your pool with an extra-powerful punch of chlorine in the form of a shock treatment. Shocking your pool is easy: Use a shock treatment to bring your 10 to 12 PPM.

Algae can wreak havoc on your pool over the winter. Not only can it cause your pool water to become green or cloudy, but it often results in unpleasant odors and it can even clog up your pool filter. Winterizing algaecide can be added to your pool once the chlorine levels are sitting between 1 and 3 ppm

Professional Winterization: The Long Island Advantage

For Long Island pool owners, professional winterization services like those offered by Pool Closing Long Island, NY specialists understand the unique challenges of our regional climate. Long Island winters don’t mess around. Temperatures drop fast, stay low, and can destroy an improperly winterized pool in a single freeze cycle. It’s a precise process of chemical balancing, equipment shutdown, plumbing protection, and systematic winterization that prevents thousands in damage.

The best time for pool closing in Nassau and Suffolk County is typically mid to late October, when nighttime temperatures consistently drop below 50 degrees. You don’t want to close too early and waste swimming time, but you also can’t wait until the first freeze. Once temperatures hit freezing, any water left in your plumbing lines can cause expensive damage overnight. Most Long Island pools should be winterized by Halloween to be safe.

The Cost of Getting It Wrong

We don’t recommend partial DIY winterization because pool closing is a system – every step depends on the others being done correctly. The most expensive mistakes happen when homeowners try to save money by doing part of the winterization themselves. For example, improper chemical balancing can cause staining and surface damage that costs thousands to repair. Incomplete plumbing blow-out can result in freeze damage that destroys your entire circulation system. Professional winterization costs a few hundred dollars, while fixing winterization mistakes often costs thousands.

Protecting Your Investment

Stops staining: Your pool water will be sitting without chlorine for several months, taking away your best line of defense from organic and inorganic stains that result from debris that may settle on the bottom, or from foreign debris entering the pool over the winter. Keeping the pH and other chemicals properly balanced helps to stop these stains from occurring. Prevents worry: By taking care of the pool chemicals at the right time, you have peace of mind that your pool will be in good order in the spring, instead of spending a long winter worrying.

Chemical balance before closing isn’t just about water quality – it’s about protecting the significant investment you’ve made in your backyard oasis. Chemical balance before closing prevents damage to the pool. Even though your pool will be covered and quiet for the next few months, it’s important to maintain the water and chemical balance before you close it. Closing your pool properly can save you a lot of work and expense when it comes time to open it back up for the summer.

By following proper chemical balancing procedures before winterization, Long Island pool owners can ensure their pools survive the harsh winter months and emerge ready for another season of family enjoyment. The investment in professional winterization services pays dividends in reduced spring cleanup, equipment longevity, and peace of mind throughout the winter months.