Green water or planktic algae are common problems in swimming pools. Once the algae has had time to build up, it can take several chemicals and a few days to resolve. Regular maintenance can easily prevent algae reoccurrences in your pool.
Step 1 Chlorine is the preferred pool algaecide.
Chlorine is the preferred pool algaecide. If the water is green or clearly contains algae clusters, there is not enough chlorine in the pool. Adding the pool with a large amount of chlorine is the most effective way to kill the algae buildup and restore pool hygiene. This usually takes 1-3 days, but can take up to a week if the pool conditions are poor.
Step 2 Scrub the pool wall and bottom.
Scrub the walls and bottom of the pool. Brush off as much algae as you can. This reduces the time it takes to kill and remove the algae. Pay special attention to the nooks and crannies where algae often gather behind steps and escalators. Make sure the brush fits the pool. Steel brushes are effective for concrete, while nylon brushes are suitable for vinyl pools.
Step 3 Check the safety of algaecide in swimming pool.
Check the safety information of the algaecide. Using this method can result in exposure to dangerous chemicals. So, be sure to read the safety information on the label first. At a minimum, follow the safety standards for general pool algae removers:
- Wear gloves, goggles, and clothing to cover your skin. Wash your hands after use and check your clothes for chemicals.
- Avoid inhaling chemicals. Be careful when handling algaecide in windy weather.
- Be sure to add the algaecide to the water, rather than adding the water to the algaecide. Do not return the wet spoon to the container.
- Algaecide should be stored in an airtight fireproof container, away from children, on different shelves on the same floor (not one on top of the other). There are a lot of pool dealginates that explode when they come into contact with each other.
Step 4 Adjust the pH value of the pool.
Adjust the pool pH. Measure the pH of the pool water with a pool pH kit. If the pH is higher than 7.6 (which usually occurs when algae blooms), add a ph-lowering agent (such as sodium bisulfate) to the pool according to label instructions. The target pH is between 7.2 and 7.6, which makes chlorine more effective and reduces the growth of infection. Wait for at least a few hours and then test the pool water again.
Kits using tablets or droppers are much more accurate than test paper. If the pH is back to normal but the total alkalinity is higher than 120 ppm, check the pH reducer label for instructions on bringing the total alkalinity down to 80-120.
Step 5 Choose a pool algaecide
- Choose a pool algae remover. Chlorine used for routine pool treatment may not be the best option for removing algae. Ideally, you should use pool specific liquid chlorine. Liquid chlorine should contain sodium hypochlorite, calcium hypochlorite or lithium hypochlorite.
- If it is hard water, calcium hypochlorite should not be used.
- Hypochlorite products are flammable and explosive. Lithium is safer but also more expensive.
- Chlorine (such as dichloride or trichloride) containing stabilizers that should not be added to the pool in large quantities should not be used in granules or tablets.
Step 6 Add large doses of swimming algaecide
Add a large dose of algaecide. Check the label for algaecide. To combat algae, use twice the dosage recommended in the instructions for conventional algaecide. Triple the dose if the pool water is very cloudy, and quadruple the dose if you can’t even see the top of the ladder. While the pool filter is running, add the algaecide directly to the pool along the sides of the pool. (For vinyl pool linings, pour the algae remover into a bucket of pool water first to avoid discoloration.)
Warning – Liquid chlorine can explode and produce corrosive gases when exposed to tablets or granules of chlorine. Never pour liquid chlorine into a pool skimmer or any object containing these substances.
Step 7 Retest the pool the next day.
- Retest the pool the next day. After the pool filter runs for 12-24 hours, test the pool again. The killed algae turns white or gray and floats in the pool water or settles on the bottom of the pool. Whether or not the algae are killed, the pool water is tested again for new chlorine levels and pH levels.
- If chlorine levels are high (2-5 ppm) but algae is still present, these levels should be maintained for the next few days.
- If chlorine levels rise but remain below 2ppm, a second algae elimination should be implemented the next night.
- If the chlorine content of the pool water does not change significantly, the cyanuric acid in the pool water may be excessive (more than 50 ppm). This is caused by the use of chlorine in granules or tablets, which can “lock” the chlorine into an unusable form. The only solution to this situation is to repeatedly (sometimes multiple times) administer an algaecide to remove the algae, or partially empty the pool.
- A large number of fallen leaves or other substances in the pool can also eat up the chlorine in the pool water. If the pool is not used for a long time, it may take a full week and several dealginate dealgation to correct.
Step 8 Brush and test every day.
- Scrub and test daily. Scrub vigorously to prevent new algae from growing on the walls of the pool. The chlorine will kill the algae in the next few days. Daily testing to confirm chlorine levels and pH levels are within acceptable ranges.
- The index values of a well-maintained pool are roughly as follows: free chlorine: 2-4ppm, pH: 7.2-7.6, alkalinity: 80-120ppm, calcium hardness: 200-400ppm. Small standard differences are common, so small deviations should not be a problem.
