If your levels are off, you'll need to do a more extensive maintenance routine to balance the chemistry of the water and kill the bacteria and algae. 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.
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.
If the pH value is not between 7.2 and 7.6, there is a risk that algae may grow in the pool. However, algae can get into the pool even if the pH is right. For this reason, the pool has to be disinfected with chlorine or swimming pool salt, for example. These products ensure that bacteria and algae cannot grow.
Test the water chemistry.
A normal chlorine level reading is 1-3 ppm. Normal pH levels should be between 7.4 and 7.6. If it is at 7.5, that is the ideal level for algae annihilation!
"Low pH levels can eliminate harmful blooms of golden algae, one cause of massive fish kills." ScienceDaily.
Most Algae Grows in High-pH Environments
Most types of algae typically enjoy higher pH levels, ranging from 8.2 to 8.7. Once algae starts growing, it can further raise the pH level in your pool and cause more algae growth.
Water with a high pH level reduces chlorine's effectiveness. This can lead to other problems like cloudy water and algae buildup.
Barley straw is a natural way to fight algae. On contact with water, the straw starts to break down, and as it does so it releases peroxides into the water which combat algae. Available in mini bales, or as a concentrated extract of barley straw liquid, it's a natural way of chemically fighting algae.
Improper pH levels: Ideally, your pool should have a pH of right around 7.4. If your pH changes for some reason, it will allow algae and bacteria to thrive. Most likely, if the pH level in your pool is wrong, it will develop green water.
Your pool is probably a green cloudy mess, so you'll want to add two chemicals to begin the clearing process: Pool Acid – also known as Muriatic Acid. Pool Bleach (bought in the big yellow jugs) also known as Sodium Hypochlorite.
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.
Highly acidic environments are inhabited by acidophilic as well as acidotolerant algae. Acidophilic algae are adapted to pH values as low as 0.05 and unable to grow at neutral pH. A prerequisite for thriving at low pH is the reduction of proton influx and an increase in proton pump efficiency.
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.
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 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.
Algae is certainly the cause of the green, but an imbalance of pH and/or alkalinity is why you have algae in the first place (while there is adequate chlorine).
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.
A good rule of thumb is to never mix pool chemicals with each other. After adding Calcium Hypochlorite a user should always wait 24 hours before adding chemicals that would alter their pH.
Bleach is great for killing algae (and other organisms that may lurk in your tanks) and for keeping it from coming back.
Shock Your Pool
Shocking is the process of adding chemicals to your pool to raise chlorine levels and kill bacteria and algae. We recommend using a calcium hypochlorite shock to treat your algae problems.
Bicarbonate, the active ingredient in baking soda, is an effective spot treatment to help kill the algae and loosen it from the wall. Make sure you really get every last particle free; black algae has particularly long and stubborn roots which makes it a persistent strand.
Rainfall dilutes pool chemistry levels and lowers the readings for pH, alkalinity, hardness, stabilizer, and chlorine. Rainfall does not contain chlorine. As well, rainfall brings with it small amounts of contaminants that are washed into the pool.
Excess nitrogen and phosphorus cause an overgrowth of algae in a short period of time, also called algae blooms. The overgrowth of algae consumes oxygen and blocks sunlight from underwater plants.
When chlorine levels are too high, the water's pH will start to decrease, which can eventually lead to corrosion. However, liquid chlorine has a pH of 13 and can cause the water's pH to increase.