(1 bag) of shock per 10,000 gallons of pool water. That may be fine for normal conditions, but if you have a severe algae attack, a triple shock is needed. 1 bag will get reach 7-9 ppm, but for 30 ppm, you need 3, 4 or sometimes even 5+ lbs per 10,000 gallons of pool 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.
A good rule to remember is to use one bag of shock (1 gallon of liquid chlorine) per 10,000 gallons.
How much shock do I need to shock my pool? A simple ratio and a standard rule of thumb to follow when you shock your pool is to dissolve one pound of either calcium hypochlorite or sodium dichlor for every 10,000 gallons of pool water.
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.
Algaecide should be used after each shock treatment, so it has a better chance to support your chlorine as it works its magic. Be sure to shock your pool first, then when the chlorine levels of your pool return to normal, add the correct amount of algaecide to several places around your pool while your pump is running.
A pool filter should be run for a minimum of 6 hours after shocking a swimming pool. This is to allow the filter to clean the water and give the shock enough time to fully mix with the pool water. Running the filter after shocking for 24 hours to 7 days is necessary if the pool has a large amount of algae.
Pools can immediately turn green after shocking when they have metals like copper in the water. These metals oxidise when exposed to high levels of chlorine which makes the pool water turn green. Adding a metal control product such as Zodiac Metal Remover will help to restore the pool water.
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.
How Often Should I Shock My 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.
After Shocking Your Pool
It is safe to swim once your chlorine levels are around 5 ppm or after 24 hours. It is always best to test first!
Typically for granular shock, you'll need one pound for every 10,000 to 13,500 gallons of pool water.
Light Green or Teal 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.
Oxidize (shock) weekly using 1 lbs. of Burn Out 35®, per 6,000 gallons of water. NOTE: Be sure to remove your cover before shocking and leave it off at least 8 hours.
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.
If you need to mildly shock a 30,000-gallon pool by raising the free chlorine concentration to 5 ppm, you need 2.5 gallons of bleach. To raise it to 10 ppm, you need 5 gallons.
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.
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.
Pool water turns green because of algae in the water. Algae can grow rapidly, particularly when it's warm like Summer, which is why it can surprise you overnight. This generally comes down to an imbalance or lack of chlorine in the water.
If your pool is still green after 24 hours, there may be too much of the wrong chemicals, for example an excess of phosphate or cyanuric acid (“stabilizer”). It will take a while for the cloudiness to go away. For a sand filter, it will take a week or more.