Swimming Pool Blog


How to Add Pool Chemicals During Winter

How to Add Pool Chemicals During Winter

by Alicia Harris, October 16, 2018

How to Add Pool Chemicals During Winter

winter pool care

There are many reasons one might add chemicals to a covered swimming pool during the winter months. Perhaps the fall weather was warmer than anticipated, and the winter chemicals were used up quickly fighting off algae. Maybe it was a wet winter, and rainwater or snowmelt passing through the cover diluted the chemicals too much. It could be early spring, and you’re just trying to keep the water balanced and recharge algaecide levels prior to opening. No matter the reason, the desired result is always the same - to keep the pool water clean for an easier spring opening!

 

Winter Chemistry Basics

Maintaining winter water chemistry is highly recommended for pools using a mesh cover, but it’s also a good idea for pools with solid covers. Unlike summer pools, which are tested and balanced several times each week, a closed winter pool only needs to be monitored once or twice per month. If you plan to leave your pool uncovered for the winter, anticipate a few extra maintenance steps to keep the pool in top shape.

winter pool maintenance

Testing frequency is also dependent on weather conditions. Since it’s a little tough to test and balance frozen water, this “once a month” winter pool care guideline only applies to thawed swimming pools. To test the water, simply pull back a small portion of the pool cover and use your chemical testing kit to monitor water balance, including sanitizer levels, pH, alkalinity and calcium hardness.

Common pool chemicals added during the off-season include water balancers, enzymes, algaecides, sanitizers and non-chlorine oxidizers. Although extra winter chemicals are not always required after closing the pool, most pool owners find that maintaining water chemistry and topping off winter chemicals during the cooler months can save quite a bit of time, money and energy once the pool cover comes off.

If you ARE planning on adding chemicals, listen up! To maximize effectiveness and avoid pool damage, it’s extremely important to circulate the pool. Granular and liquid chemicals can both damage pool surfaces if allowed to settle on the floor and/or remain concentrated in one location. Chlorine, in particular, can discolor or permanently damage vinyl liners and plaster. Circulating the water won’t be as simple without a filtration pump to help you, but it’s still quite doable!

Common Chemistry Problems

pool balancing chemicalsOne of the most common issues with winter pool chemistry is a sharply changing pH level. This can be problematic, not only for the effectiveness of your winter chemicals, but also for your pool as a whole. High pH causes calcium scale to form around the waterline, and low pH can bring issues with corrosion and staining. For this and any other water chemistry issues, use water balancing chemicals to get the pool water back on track.

Another common issue stems from low sanitizer or algaecide levels, which can allow algae blooms to occur. Test the water regularly to ensure sanitizer levels stay within the recommended range. Also check for visible algae growth as the days start getting warmer, and add more algaecide in the weeks leading up to pool opening day. We recommend using a long-lasting product like Algaecide 60+ or Winter Algaecide.

Adding Winter Chemicals

When adding any chemicals, follow the manufacturer’s instructions for dosage, safety and chemical compatibility. Make sure granular chemicals are fully dissolved before adding to the pool. As mentioned earlier, proper circulation of chemicals is extremely important to prevent damage in a winterized pool. Start by distributing chemicals along the edge of the pool, pouring as you wallk. The cover should be pulled back on one or two sides to allow clear access to the water, but make sure the cover is clean to prevent debris and dirty water from getting in your pool!

Without the help of a filter pump (which is likely already drained and winterized), there are still a couple of easy ways to make sure added chemicals get distributed in your pool.

submersible pool pump

The first method is the cheapest, but will require a little extra effort on your part - just use a long-handled pool brush to agitate the water and circulate the chemicals around the pool.

The second method is much easier, but it requires the use of a submersible pump. If you already have one for your solid winter cover, then you should be all set! Set the pump in the water on one side of the pool (opt for the deep end if the cord is long enough), and extend the hose attachment to the opposite end of the pool. Leave the pump on for an hour or two to get the water moving. A submersible pump with a low GPM flow rate may need to run a little longer. You can also use the submersible pump in conjunction with the pool brush method to maximize chemical distribution in a shorter time period.


No matter what you need, Pool Center has the right products to maintain your pool throughout the year. Our selection of chlorine-free winter pool kits are safe for all pool surfaces, and all kits are precisely formulated to keep the water clean and clear until it’s time to open the pool again. The classic winter kits and ultimate closing kits are both designed to keep your pool in top shape all winter without the need for extra chemicals. But, if changing weather or altered chemistry leaves you needing more, our selection of high quality winter chemicals and water balancers can help you out. Still have questions about winter pool maintenance? Give us a call!