Bacteria, algae and microscopic contaminants, such as urine, sweat, sunscreen and beauty products, take a toll on your swimming pool's water chemistry. These substances, when present in your pool water, accelerate chlorine demand and can affect your chlorine's ability to maintain properly sanitized water.
Could be a couple things. Poor circulation or not enough time your pump is running or a dirty filter seem like the obvious things to check first. Is your combined chlorine higher than your free chlorine? You could also just have some lingering algae that's eating up your chlorine.
Every swimmer introduces organic materials such as sweat, sunscreen, and body oils that instantly demolish the free chlorine residuals. Higher levels of contaminants: The mud, leaves, and other debris that collect at the bottom of the pool absorb chlorine as it continues breaking down the contaminants.
Algae, bacteria, or fungus growth. Debris or contaminants from winter or periods of inactivity. Heavy pool usage or high bather load, especially during summer. Biofilm or organic material in the water, such as sunscreen, leaves, or algae.
Too much Stabilizer: A chlorine lock can occur when you have added too much cyanuric acid, or stabilizer, into your pool water. Stabilizer is a chemical intended to protect chlorine from burning off too quickly from UV rays. If you get too much of it, it can completely block your chlorine and make it ineffective.
Two different chemical agents that can reduce chlorine levels are Sodium Thiosulfate and Pool-Grade Hydrogen Peroxide (specific to pool treatment). Be sure to test your water after using one of these agents as they tend to impact pH, sometimes dramatically.
Low/No chlorine production
The factors that affect chlorine levels include the summer heat, poor filtration, bather load, and the frequency of use. It's also possible that the time period you set is too short, the chlorine output level is too low, or the filter needs backwashing.
To accurately measure chlorine levels, use pool test strips or a liquid test kit, which you can find at any pool supply store. These tests also help you monitor other important pool chemical levels like pH, alkalinity, and calcium hardness. Under normal conditions, you should add a chlorine tablet every 3-7 days.
High chlorine levels can also be caused by using too much liquid chlorine or chlorine tablets, not using a chlorine stabilizer, or having an improperly maintained pool.
You may think of using baking soda to help you with your algae problem, but unfortunately, it won't help.
Direct sunlight (UV)
Direct sunlight breaks down chlorine. Without a stabilizer (cyanuric acid) in the water, as much as 90% of free available chlorine could be destroyed within just two or three hours.
The only way to cure chlorine demand is to give your pool the chlorine that it needs through consistently shock treatments. A general rule to follow is to use 3 pounds of calcium hypochlorite pool shock for every 10,000 gallons of pool water. This may vary depending on the degree of chlorine demand that your pool has.
If you just added chlorine or a chlorine-based shock to your pool and you still have a low chlorine level, there's a chlorine demand problem. In order to cure chlorine demand, triple shock your pool with calcium hypochlorite or cal-hypo shock.
Bacteria, algae and microscopic contaminants, such as urine, sweat, sunscreen and beauty products, take a toll on your swimming pool's water chemistry. These substances, when present in your pool water, accelerate chlorine demand and can affect your chlorine's ability to maintain properly sanitized water.
The easiest way to ascertain if the chlorinator is working is to make sure the cell is clean by checking the needle or production lights. Ensure there is enough salt in the pool. On the chlorinator box there should be a light or dial that indicates it is working.
Raising pool chlorine can be much easier than trying to lower chlorine levels. Simply adding chlorine in the form of chlorine tablets, granular chlorine, liquid shock or powder shock will increase the total amount of chlorine within the pool.
Is it possible to shock your pool too much? Yes—excessive shocking of your pool will keep it at an elevated chlorine level. This will cause irritation of the skin and eyes as well as excessive wear and tear on your pool filter system, including excessive corrosion of all metal parts.
This issue is brought about by the presence of too much cyanuric acid, which can overpower the free chlorine in your pool. Cyanuric acid (CYA), also known as stabiliser, is used to protect the unstabilised chlorine in your water. Without it, chlorine can be broken down by UV rays from the sun, rendering it ineffective.
Make sure the pool is clean and chlorine is at the proper level. Read the dosage on the bottle for recommendations. For liquid or powder stabilizer, add to the pool by walking around the perimeter and slowly adding stabilizer along the edges. If using powder stabilizer, brush pool down to promote mixing.
The fastest and most accepted way to break a chlorine lock is by shocking your pool and achieving breakpoint chlorination. This is done by triple shocking your pool with UNSTABILISED CHLORINE. Don't use stabilised chlorine as the added cyanuric acid will worsen the problem.
Cal-hypo is an unstabilized form of chlorine, meaning it doesn't contain Cyanuric Acid. Don't pre-mix cal-hypo before adding to the pool. Broadcast it directly over the pool surface, and disperse settled granules with a pool brush. Always follow the label directions.
Before going to the swimming pool, always apply some essential oil like olive oil, coconut oil, or baby oil. It will create a barrier between the chlorine water and the skin. Before going to swim, it's always necessary to take a shower because if the skin is dry, it will help to quickly absorb the chlorinated water.