Chlorine is a vital element of a swimming pool that helps remove harmful microbes and contaminants to make the pool safe for swimming. However free chlorine level can drop down in the pool due to high chlorine demand, rough use, high CYA level, or insufficient salt in pool water. In this case, knowing how to raise free chlorine in pool can help maintain the perfect free chlorine level in your pool.
To raise free chlorine in your pool, test the pool water, make sure it has the proper level of pH, alkalinity, and CYA and then you can apply cal-hypo shock, sodium dichlor shock or dichlor granules.
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Some Effective Ways To Raise Free Chlorine in Your Pool Water
If you want to raise free chlorine in your pool, first clean all contaminants from your pool. Test the water and make sure its alkalinity, pH, and cyanuric acid levels are in good range. Then add these ingredients to your pool to raise its free chlorine level:
1. Cal-Hypo Shock
If you have a typical chlorine pool, you can apply cal-hypo shock on it to raise free chlorine quickly. This is because it’s the strongest and most unstabilized kind of shock. However, you’ll have to add cel-hypo shock at night or on cloudy days to avoid destroying the shock due to the sun’s UV rays. Then wait around 8 hours before using the pool for swimming.
If your pool has higher chlorine demand, triple the shock. This chlorine-based shock is also helpful in increasing free chlorine level minimum of 10 ppm. However apply to add cel-hypo, and keep your pool uncovered to let the water come in contact with air to remove oxidation gasses.
2. Sodium Dichlor Shock
If you want to raise free chlorine in a saltwater pool, add dichlor shock. It will raise the free chlorine level without causing scale accumulation on the saltwater generator. However, this type of shock can increase cyanuric acid levels. So if your pool has a high cyanotic acid level, you should avoid this shock.
3. Dichlor Granules
dichlor granules are usually used in indoor pools, hot tubs, and spas. However, you can use this product on above above-ground pool as well. Dichlor granules contain quick dissolving properties that help them raise free chlorine levels very quickly without affecting alkalinity and pH levels. However, dichlor is an expensive product and it isn’t much helpful with chlorinators.
Why Do Free Chlorine Levels Drop Down in Pool Water?
Below are some potential reasons that can reduce the free chlorine level in your pool water:
High Chlorine Demand
If your pool has lots of debris or a higher bather load, its free chlorine level can drop down quickly. This is because chlorine sanitises contaminants in water. That’s why your pool’s free chlorine level can get lower during winter and after rainfall or runoff. If you want to treat the high chlorine demand of your pool, triple shock the pool using calcium hypochlorite.
Rough Use
If your pool has lots of swimmers and they use the pool more often, their sunscreen, oil, or dirt may contaminate the pool over time. Hence your pool’s free chlorine level can drop down. If so, you’ll need to shock the pool weekly to maintain a perfect free chlorine level.
Low Cyanotic Acid Levels
If you use unstabilized chlorine such as bleach or chlorine on your tool to sanitize water, it can reduce the free chlorine level in sunlight. This is because the rays of the sun break chlorine. If so, check the cyanuric acid level of your pool regularly and add a chlorine stabilizer to maintain the chlorine level.
High Cyanotic Acid Levels
High CYA levels in the pool reduce the sanitizing ability of chlorine. If so, add 3-inch chlorine tablets in the pool to raise cyanuric acid and keep the CYA level within 30 to 50 ppm.
Increased Contaminants
Heavy rain storms can add lots of contaminants to the pool which can lower the free chlorine level. If you want to increase the free chlorine level in such a pool, clean debris after the storm and shock the pool after runoff.
Insufficient Salt Pool
If you have a saltwater pool and it has saltwater generators, its free chlorine level can drop down due to insufficient salt. Salt cells require a specific level of salinity to work and they should sit about 5000 ppm. Check your pool’s salinity level every month to maintain the salt level and inspect the salt water generator to keep it in good condition.
Also Read: How To Make A Room Less Stuffy?
Why Can’t You Get Chlorine Reading When Testing Pool Water?
If you can’t get free chlorine reading while testing your pool, it can be the result of high chlorine demand. The higher chlorine demand can prevent you from maintaining proper free chlorine levels in pool water even when it looks properly maintained and balanced.
High chlorine demand means the oxidation level in your pool is increased and it consumes chlorine level quicker than you can increase the chlorine level by adding a salt chlorinator. It can happen particularly when your pool has lots of contamination, low chlorine stabilizer level, or pH level.
What if Your Pool Water Turns Green After Shocking To Raise The Free Chlorine Level?
If your pool’s free chlorine level is still low after the shock, it can be the result of the metals in the water. If so, your pool water will turn green due to metal oxidization exposed to chlorine. In this case, you can restore pool water by adding a Zodiac metal remover or bypassing the pool heater. Your pool’s free chlorine level won’t also rise if you use excessive copper-based algeacides in the pool. If so, you have to use metal-free algaecide to fix the problem. If your pool water has more than 50 ppm CYA level, it will make the chlorine less effective.
So you have to make sure that your pool’s cyanuric acid level is within 30 to 50 ppm before adding chlorine to it to raise the free chlorine level. If your pool water has lots of phosphates, it can also prevent you from raising the free chlorine level in your pool. So before shocking your pool, make sure your pool has below 500 ppb phosphate level.
FAQs on How To Raise Free Chlorine In Pool
Can You Swim in The Pool if Free Chlorine Level is Low?
Pool owners add chlorine to swimming pools to remove harmful bacteria, algae, and parasites from the water. If your pool water has low chlorine, it means it will allow microbes to build up. So you shouldn’t swim in the pool if free chlorine level is low as it will be unhealthy and unsanitary for you.
How Long After Chlorine Can You Swim in The Pool?
If you add chlorine to your pool water, wait a minimum of 2 to 4 hours before you start swimming in it. However, it’s safe to swim in your pool after 24 hours of adding chlorine or the water gets around 5 ppm chlorine level.
What To Do if Total Chlorine is Higher Than Free Chlorine in Your Pool?
If your pool water has higher total chlorine than free chlorine, the pool has lots of contaminants. In this case, deduct the free chlorine value from the total chlorine value to determine the amount of combined chlorine. If you find that combined chlorine is over 0.5 ppm, shock your pool to maintain a balance between free chlorine and total chlorine.
Final Words
If you want to raise free chlorine in the pool quickly, add granular chlorine, and chlorine tablets, or apply chlorinated shock on your pool. However, before trying to increase the free chlorine level, make sure your pool water has the right pH, alkalinity, and CYA levels to make the chlorine shock more effective. You should also vacuum your pool regularly and maintain it yearly to keep free chlorine at the perfect level. But you should call a professional pool cleaner to restore your pool’s freshness after heavy rainfall, storm, or runoff.
