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.
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.
Shock & Filter the Water
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 regularly will help to keep the water clean and free of contaminants. You should aim to shock your pool about once a week, with the additional shock after heavy use. Some tell-tale signs that your pool needs to be shocked are cloudy, foamy, green, or odourous water.
Adding Shock Directly Into The Pool Water
Don't worry—you can't overshock your pool. But beyond fashion faux pas, adding shock directly to the pool water if you have a vinyl liner can be a disaster. The shock granules will sink the bottom and bleach out your liner.
Although, if you overdo the shock treatment, you risk getting green hair from chlorine due to the excess chlorine oxidizing the copper in the water. You can execute a shock treatment with a few different types of pool shock, just be mindful of how much you're using.
The Department of Environmental Health recommends avoiding activities such as swimming, surfing, and diving for 72 hours after it rains. Research has shown that the risk of infection is the highest during and the day after rain, and declines to around normal levels after three days.
Rainwater itself does not cause algae, but it can provide the right environment for algae. Rain will bring phosphates, nitrates and other organic contaminants into the pool. As we discussed earlier, rain also reduces chlorine levels.
When rainwater and 'run off' enter the pool, they can change your water's pH, calcium hardness, total dissolved solids (TDS), alkalinity, and other chemical levels as well as bring contaminants such as dirt and debris into the pool.
It's not absolutely necessary to shock it after rain, but it's not a bad idea either. Now that you know how to drain water from your pool after rain, just be sure to do that first, then balance the water, then shock. Remember to wait until dusk before adding any pool shock.
"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.
The extra filtering will help clean out the impurities rain has introduced into your pool's water. Pool pumps are made to withstand rain and it is beneficial to run your pump during or after rain.
So shock your pool and keep the pump running.
And if you're wondering if you can shock a pool IN the rain, the answer is yes. Just remember that rainwater adds more contaminants, so it won't be as effective as shocking during dry weather.
It's pretty tough to over-shock your pool; shocking your pool two days in a row with the proper dosage for your pool volume shouldn't be a problem – and in fact, is sometimes even needed to rid your pool of algae and other contaminants.
Before you start pouring shock in the pool, the first step is to brush the sides and floor of your pool to loosen all the algae. Doing this breaks the skin and allows the pool shock to more easily kill the algae. Once you've done this, it is important to make sure you have the proper pH level in your water.
You cannot overshock a swimming pool or add too much. Adding too much shock or overshocking your pool will kill off algae. The negative of adding too much shock is it will upset the chemical balance of your pool.
It's often recommended to shock your pool once a week. If you don't do it every week, you should at least do it every other week. This is necessary to maintain your pool's water chemistry. If you have a lot of people over in your pool or have a party, you may want to shock your pool more frequently.
Shock is chlorine, in a high dose, meant to shock your pool and raise the chlorine level quickly. Chlorine tabs (placed in a chlorinator, floater, or skimmer basket) maintain a chlorine residual in the water. You do need to use both tabs and shock.
It Should Not Be Done Together
This is because when you mix chlorine and algaecide together, it renders both of them useless. Hence, you should first shock the pool and wait for the chlorine levels to fall below 5 PPM. Only then should you introduce algaecide to get the best results.
Light Green or Teal Pool Water:
In this case, you should double shock your swimming pool water. To double shock, you will need to add 2 pounds for every 10,000 gallons of water. For instance, if you pool is 20,000 gallons, you will add 4 pounds of shock.
Swimming pool builders often install overflow drains near the rim of the pool that prevent flooding most of the time. If you don't have an overflow drain, or if it is clogged, it is possible for periods of unusually heavy rain to overflow your pool.
You don't need to drain your pool, as there is no risk to your pool by it being full. The only thing you lose with a pool filled to the rim is your skimmer's surface cleaning action. Overall, it still draws water and the equipment is just fine.