Give your pool a good shock treatment 1 to 2 days before the storm hits. You can bring the chlorine level up pretty high to prolong the pool being depleted of chlorine. Run the pool for about 24hrs after the shock treatment to allow the treatment to make its way throughout the entire pool.
Use shock treatment on your pool one or two days before the storm. Add chlorine levels significantly during the treatment and let it run for 24 hours to allow the treatment to fill the entire pool. Make sure all furniture or items around your pool are safe to prevent injury to persons or property.
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.
While light rain will have little, if any, effect on pool water, heavy rainfall can dilute a swimming pool's chlorine levels, allowing bacteria and algae to start growing. Rain can also lower a pool's pH. Chlorine becomes hyperactive at a low pH, causing it to be used up more quickly than normal.
Heavy rains will deplete many of the chemistry levels in your pool. Generally your alkalinity will drop significantly. It is a good idea to have Alkalinity, Muriatic Acid, Chlorine (or Salt), and Shock on hand to be able to test your water and treat your pool immediately after the rain stops.
Shocking helps sanitize any contaminants or materials that were introduced to the water during the storm. Run your system for at least 12 hours to ensure proper filtration and circulation. This removes dirt and debris, and also assists with circulating the chlorine throughout your pool.
Shocking your pool isn't necessary, although, it's not a bad idea either. If you get an extremely heavy rain fall, you could shock your pool for good measure. This will help fight off any contaminants that the rain may have brought to your pool.
If your pool pump manufacturer has declared your pump is rain safe, you can leave it on in rainfall. Nevertheless, during a thunderstorm, it is highly recommended that you switch off and unplug your pool pump to prevent any costly and irreversible damages to your pool equipment.
Because after heavy rain, pools undergo a few changes on both a chemical and physical level. Rainwater affects pH and Alkalinity levels, while excess rainfall adds extra water in the pool that you don't need. Not to mention all the contaminants that rainstorms sweep into your water.
If the pool is still very cloudy or green, you may need to shock it to make it safe to swim in again. First, make sure that the filter system is working properly and the chemicals are still at the proper levels. Next, mix up your chlorine shock (hyperchlorinate) treatment.
Answer: It should not matter much. It could help to filter debris and contaminants the rain washes into the pool. However, lightning can be a concern with the filter running.
The most important factor though is the size of the pool. You'll need about 52-104 oz of liquid chlorine per 10,000 gallons of water. This amount should get the chlorine level to between 5 and 10 ppm.
"Heavy rain dilutes pool chemicals, especially salt and chlorine, which causes the pool to turn green. This means the water is not sanitised or healthy, so it's vital to address this.
It is recommended to wait at least 20 minutes to an hour after adding water balancing chemicals. You should wait 2-4 hours (or one full cycle through the filter) to swim from the moment you use calcium chloride in your pool. It is safe to swim once your chlorine levels are around 5 ppm or after 24 hours.
The procedure for adding granular chlorine is pretty much the same as adding calcium chloride or sodium bicarb to a pool. Measure the dry chemical, pre-dissolve in a bucket, and pour around the perimeter of the pool (never into the skimmer directly).
Sodium hypochlorite (also known as liquid chlorine) is another frequently used option for shocking pool water. This is a common choice in pool shock because you can pour the solution directly into the pool without having to dissolve the chlorine in water beforehand.
What's important for you to know: You shouldn't swim in a pool that's green until you test the chemical levels, like the officials in Rio did before the diving event began. It's the balance of things like chlorine, pH, and alkalinity in a pool that keeps it sterilized.
So if the pool water isn't cloudy and the 'dirt' is clinging to the walls after brushing, the problem is likely be yellow/mustard algae. Yellow/ Mustard algae is very resistant to even high chlorine levels and will grow and thrive in a chemically well-balanced pool.
The free chlorine levels might be low.
But be careful—adding too much chlorine in pool water can cause those metals to oxidize and turn the pool a different shade of green.
At the first sign of an incoming storm, you should turn off and unplug your pump. If this is left running during a storm, the motor may suffer electrical damage and short out.
Covering a heated swimming pool at night will reduce heat loss. That means warmer water, which is what anyone who has ever gone swimming in a chilly pool can tell you is very important.
Baking Soda and Green, Blue, or Yellow Algae
You'll need to use an algaecide to kill the algae and superchlorinate your pool to clear the water. After this treatment, test your pH and alkalinity and add baking soda to raise alkalinity to at least 100 ppm and pH to between 7.2 and 7.8.
One of the causes of a high chlorine demand is an excessive buildup of algae and phosphates. Although you're adding chlorine to your water, bacteria or algae are overpowering the chemicals causing it not to show up on tests strips or in water kits.
Excess chlorine can alter the pH level of the water in the pool, making it more acidic. The acid levels can cause any of the following symptoms: Irritant dermatitis which is a red skin rash characterized by raised itchy red bumps. Eye irritation and over-dilated blood vessels in the eyes.