Basic Checks First: Filter Run Time: Make sure your filter is running for at least 10 to 12 hours total per day, specifically during the daylight hours when the sun is out. Circulation: Check that you have strong circulation while on high speed.
The consistent inability to maintain chlorine levels is also called “chlorine demand” and is most often caused by a high level of inorganic and organic contaminants in the water. Those contaminants force the chlorine to work extremely hard to oxidize them, leaving little chlorine to protect swimmers.
You have one of two issues. 1) your CYA levels aren't high enough so the sun is destroying your chlorine faster than you can keep putting it in or 2) and more likely is that you have chlorine demand. So something that takes awhile to get a handle on is that a tester kit can only test from 0 chlorine and up.
Chlorine demand occurs when there are a lot of organic and inorganic chemicals, minerals and other types of matter in swimming pool water that the chlorine is struggling to neutralize.
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.
Adjust the free chlorine level by raising the percentage setting of your SWCG. If that doesn't increase your free chlorine, try increasing your pump's operating time as well. If you're still experiencing problems, the cause could be early stages of algae, chloramine or ammonia, or calcium buildups in your salt cells.
A good shock product should raise the free chlorine above 5 parts per million for several hours to destroy bacteria and chloramines. Keep in mind, if you have visible algae of any kind (black algae, mustard algae or green algae), you may need to double or triple the normal dosing of pool shock to eradicate the problem.
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.
Short Summary. It is essential to regulate chlorine levels in a pool between 1-3 ppm, as levels exceeding 5 ppm can be hazardous. Swimming in a pool with high chlorine levels should be avoided. The highest safe chlorine level for a pool is 3 ppm.
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.
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.
Adding too much pool shock or putting too many chlorine tablets to the feeder can both result in very high levels of chlorine. Another common way to over-chlorinate a pool is to leave a liquid chlorine pump running all night – you'll often come in the next day to discover a greenish-looking pool.
Test Your Water Regularly, Especially During High Temperatures: Extreme heat can throw off your pool's water balance, leading to issues like increased pH levels and chlorine depletion. Regular testing with HTH™ Pool Care 6-Way Test Strips will help ensure proper pH, chlorine, alkalinity, and other chemical levels.
Using a pool chlorine floater is a common, easy way to apply tablet chlorine to a pool. Make sure the floater is designed for the type of chlorine you're using and the tablet size, either 3 inches or 1 inch. Simply drop the required number of tablets in the floater and put the floater in the pool.
Shock Your Pool: The best way to solve low free chlorine levels is through shock treatment. Shocking is a concentrated dose of chlorine added to raise the level quickly and oxidize existing contaminants.
Chlorine will burn itself off naturally. Depending on how hot it is and how high your chlorine levels are will determine the amount of time needed. It could be quick or it could take a few days.
The effect of excess chlorine in pools is an alteration in pH levels of pool water, making it more acidic. Signs of high chlorine levels can include itchy sensations in the eyes, nose and throat, nausea, vomiting, dizziness, lung irritation, and skin rashes.
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.
Sodium ascorbate will also neutralize chlorine. It is pH neutral and will not change the pH of the treated water. Sodium ascorbate is preferable for neutralizing high concentrations of chlorine.
Direct sunlight (UV)
Direct sunlight breaks down chlorine.
If you've not cleaned your pool yet and there's a lot of debris, your free chlorine level is likely low because it's busy working on cleaning all the contaminants from the debris. Clean your pool and remove debris, then test the chlorine level. Then, test your water.
Chlorine Tablets for your Pool
The time required to safely sanitize the pool with tablets alone is far greater than that of liquid chlorine. What you pay for convenience in the tablet, you ultimately sacrifice in timing should you let the pool water fall too far below recommended pH level.
Baking soda, also known as sodium bicarbonate is naturally alkaline, with a pH of 8. When you add baking soda to your pool water, you will raise both the pH and the alkalinity, improving stability and clarity. Many commercial pool products for raising alkalinity utilize baking soda as their main active ingredient.