1. Algae Growth. As algae thrive in slightly acidic water, algae growth is often the first sign your fish tank has a low pH level. With more nutrients available and accessible light, algae can spread like wildfire when pH levels drop.
Algae can grow rapidly in an alkaline medium of water. Rapid algal growth which is known as the algal bloom is totally dependent upon the high pH range. Generally, algae grow in pH ranges of 8.2 to 8.7, which is alkaline. Minerals, water, sunlight, and carbon dioxide are other requirements for algal growth.
Some Algae Grows in Low pH
Having a low pH level in your pool means your water is too acidic. Algae growth varies because not all algae live in acidic conditions. Water with a low pH balance is also harmful to your filter, allowing more algae spores to enter your pool.
If the pH is high, your chlorine is slow to react, and algae can begin to form, making the pool appear green or cloudy. If the pH is low, the chlorine will be “hyperactive”, reacting quickly, and dissipating out of the pool too rapidly, causing a low chlorine residual.
If you're treating your pool for algae, you'll want the pH to be a little higher than you would typically want, at about 7.8. This will kill the bacteria or algae. Based on your levels, you will either have to lower or raise the pH.
Control pH levels
The levels should be between 7.4-7.6. 'The pH levels of a pool must be balanced. High pH levels reduce the ability of chlorine to kill algae and other bacteria,' he adds.
If your pool is green and cloudy, it's likely an algae problem. Algae can persist in a pool even after shocking. A green pool – especially one that turned green overnight or after rain, can also be from a pool pump that isn't properly circulating water or an issue with your filtering system.
The acceptable range for pool water pH is 7.2-7.8, and the ideal pool pH is between 7.4 and 7.6. Water below a pH of 7.2 is too acidic, stinging your eyes, damaging pool liners and corroding equipment. Water above 7.8 is too alkaline and can cause skin irritation, cloudy water, and scale buildup.
Low pH water will cause etching and deterioration of plaster, grout, stone, concrete and tiling. Any vinyl surfaces will also become brittle, which increases risk of cracks and tears. All of these dissolved minerals will hold in the solution of your pool water; which can result in staining and cloudy pool water.
Aim for a pH level of between 7 and 7.6. If the water pH is higher than 8, anyone who swims in the pool is at risk of skin rashes, while a pH of lower than 7 can sting swimmers' eyes. Some of the many factors that can affect your pool's pH level include heavy rain, the number of swimmers in the pool and chemicals.
For example, marine algae strains prefer pH usually around 8.2, while freshwater strains prefer pH around 7.0. Meanwhile, spirulina (Arthrospira) prefers a pH of around 10. Second, algae require carbon dioxide, for growth and pH can affect how much is available.
Use a pool brush to vigorously scrub any pool surfaces covered in algae, including the walls, floors and steps. Apply a green algaecide according to the directions on the label. Let the water circulate for 24 hours, then brush the pool surfaces again. Vacuum or backwash to remove any remaining dead algae.
If the pH becomes too high (over 7.8), it prevents the chlorine from doing its job. If you're not checking the pH and it has risen too much, you could be adding the right amount of chlorine, but it can't work correctly, and algae will begin to grow.
Siamese Algae Eaters can grow up to about 6 inches (16cm) and hence require a tank of at least 30 gallons for better results. Water temperature should be between 75°F and 79°F and a pH range of between 6.5 and 7.0.
Water with a high pH level reduces chlorine's effectiveness. This can lead to other problems like cloudy water and algae buildup.
Remember that a low pH level is crucial to successfully shocking a pool. At a pH level of 8.0, over half of your shock is ineffective and wasted. At a pH level of 7.2, however, over 90% of your shock will become active algae and bacteria killers.
Too low a pH has a significant influence on the effect of the chlorine. If the pH level is too low, you will have to add a large amount of chlorine to ensure proper disinfection of the water. A good pH level will therefore also benefit your wallet.
The closer your pool is to this magic number, 7.5, the more you'll enjoy your swim. As it happens, pH 7.4 to 7.6 is also very good for chlorine disinfection. pH above 8.0 can cause skin irritation and at higher pH's scaling can occur upon your pool's surface.
Low pH is often caused by rainwater and debris getting into the pool. The easiest way to raise the pH in a pool is to add sodium carbonate (soda ash) or sodium bicarbonate (baking soda).
Likewise, a low pH can also cause cloudy water due to increased bacteria and algae. In this case you'll want to use a pH increaser to raise the level to at least 7.4. It's also important to keep an eye on total alkalinity.
pH Down comes in two forms: liquid acid or dry acid. Changes in the pH of pool water can be caused by many factors but one of the most significant causes is the sanitizer used. Since the sanitizer is the most frequently added chemical in pools, it can have a powerful impact on pH and overall water quality.
Pool Algae Causes
Once algae gets into your pool water, they can turn into an algae bloom if you have nitrates, out-of-balance chemicals, warm temperatures, sunlight, carbon dioxide, or phosphates. Poor water circulation, poor filtration, and not sanitising your pool will also contribute to rapid growth.
The most important test to take if your pool's still green after shocking is the pH level. Buy a kit or a test strip and test the pH because it will indicate whether you need to add other chemicals. A high pH means your water is alkaline and cloudy, especially after the shock.