No Free Chlorine In Pool After Shocking

If you are a pool owner, then at one point or another, you could have had this experience. After adding an adequate amount of shock, you discover that the free chlorine levels in the pool have not changed. This could be both discouraging and frustrating.

In this article, you will get to understand why that happens and get solutions to this problem.

Why does my pool show no chlorine after shocking?

There are many reasons why this can happen.

  • Presence of too much organic matter: Despite shocking your pool, it could be a surprise to not see chlorine show up on test kits or water kits. This could be due to the presence of organic matter. Organic matter such as algae and bacteria can lead to the rapid use of chlorine. It leads to a high demand for chlorine and is easily used up. As chlorine kills off algae and bacteria, it is depleted. So to let chlorine do its job, you can do the following:
  • Manually brush off algae from the pool walls.
    • Clean the pool filters regularly.
    • Remove debris manually from the water.
  • Inadequate levels of cyanuric acid: Cyanuric acid is a pool stabilizer that is also known as chlorine sunscreen. The essence of cyanuric acid is to prevent the rapid degradation of chlorine levels. When chlorine is added to the pool, the UV rays from the sun degrade it quickly. Cyanuric acid helps to keep the chlorine levels from degrading quickly as well. As a result, even after shocking, there is no free chlorine in the pool.
  • Excessive rain: When rain falls, the droplets carry oxygen. This can offset the balance of the water chemistry. This in turn leads to the use of more chlorine.
  • Presence of phosphate: Phosphate can get into your pool water from household cleaners. This extra phosphate can cause interference with the pool‘s current cleaners. When this interference happens, the demand for chlorine increases.
  • Excessive sunlight: In the summer months, pools tend to get exposed to excessive sunlight. The UV rays from the sun easily degrade the chlorine in the pool. This leads to the rapid depletion of chlorine levels in a pool.
  • There are two ways nitrogen affects chlorine levels. The first is this: organic nitrogen combines with chlorine to form organic chloramines. These organic chloramines now need higher levels of chlorine for oxidation. Another way in which nitrogen concentration can be an issue is this. The presence of nitrate in the pool can cause the rapid growth of algae. Indirectly, the fast growth of algae will lead to a need for more chlorine.

Will shock bring up free chlorine?

Free chlorine is chlorine readily available to sanitize. When it does its job, it becomes combined chlorine. At this point, it is no longer viable. When a pool is shocked, it breaks up the organic matter and helps boost the level of free chlorine. This raises the level of free chlorine available to work. Also, it does the job of oxidizing combined chlorine. This allows the chlorine to gas off. In turn, the pool becomes clear and comfortable to swim in.

How do I raise the free chlorine level in my pool?

The fastest way to do this is by using a chlorine-based shock. A non-chlorine-based shock will only break down combined chlorine. But one that is chlorine-based raises the chlorine levels rapidly. The main component of chlorine-based shock is calcium hypochlorite. Calcium hypochlorites are also found in bleaching and chlorine products.

The chlorine levels can be increased by simply adding any of the following:

  1. Chlorine tablets
  2. Liquid-based shock
  3. Powder shock
  4. Granular shock

Can total chlorine be less than free chlorine?

No, it can’t.

First, you must understand what total chlorine is. Total chlorine is the sum of combined chlorine and free chlorine. The combined chlorine is chlorine that has been bound by contaminants. This combination forms compounds called chloramines. In this state, chlorine is no longer useful. On the other hand, free chlorine is that which is still readily available. It can readily oxidize and destroy organic matter.

So, in essence, the total chlorine is either more than or equal to the free chlorine.

Total chlorine = Free chlorine + Combined chlorine.

How do you tell if a pool is properly chlorinated?

In practice, a pool that is properly chlorinated should have little to no odor. That characteristic smell of chlorine comes from chloramines. As stated above, they are a result of chlorine getting bound to contaminants. These contaminants include ammonia or nitrogen.

How many shocks do you need to break a chlorine lock?

A chlorine lock is when you can’t use any more chlorine, no matter how much you put in. The leading cause of this is adding too much pool stabilizer (cyanuric acid). Too much cyanuric acid prevents chlorine from being reactive. As a result, chlorine can not do its job. This is a chlorine lock.

To break a chlorine lock, you need to be technical. You will need to add a chlorine-based shock till it is ten times the value of the chloramines. This is because you want to reach a point called a “breakpoint.” At this point, the chlorine can break up the chemical bond of the chloramines.

How long does pool shock take to work?

Pool shocks start to work almost immediately. For chlorine-based pool shocks, it takes 24-48 hours to finish working. This is the time frame required for the chlorine levels to return to normal. But for lithium and non-chlorine-based shocks, they can finish working within minutes.

How long after the shock can I add chlorine?

Both shock and chlorine can be used together. They are both chlorine compounds, only that they have specific purposes. Granular shock is preferably used daily and it comes in a stabilized form. On the other hand, liquid chlorine is preferably used on a weekly basis. It is used when you want a high and rapid concentration to kill bacteria with ease. This form of chlorine is in an unstabilized form.

How do I fix a chlorine lock in my pool?

The following are methods with which you can fix a chlorine lock:

  • Drain the pool partially: Draining the pool creates a dilution effect. You reduce the pool to about half its volume, then you refill it. This way, the cyanuric acid effect will be toned down.
  • Non-chlorine shock: The non-chlorine shock oxidizes the chloramines and causes the balance to return to the water.
  • Chlorine shock: You add chlorine shock till a point called the breakpoint is reached. This is when the chemical bonds of the chloramines have been reached.

Why does my pool lose chlorine so fast?

There are some reasons why this happens:

  1. Excessive sunlight: The sun’s UV rays rapidly degrade chlorine. This makes the chlorine evaporate very fast.
  2. Inadequate stabilizers: Cyanuric acid is an important pool stabilizer. It helps to keep the chlorine in the pool for longer. When the levels are low, chlorine can easily evaporate.
  3. Presence of organic matter: The presence of debris and organic matter in the pool leads to a quick depletion of chlorine. Their presence ensures that chlorine is used up quickly. Because as the chlorine kills algae and bacteria, it is used up.

Is it safe to swim in a pool with low chlorine?

No, it is not.

It’s not a good idea because algae, bacteria, and other organic matter are in it. Over time, you can develop illnesses such as skin rashes and infections.

How many hours should you wait to swim after shocking a pool?

This depends on the kind of shock used. For chlorine-based shocks, you should wait at least 24 hours before swimming. But for non-chlorine-based shocks, you can begin swimming almost immediately.

Can you shock a pool without the pump running?

Yes, you can.

It’s true that running a pump helps make the shocking easy. But alternatively, you can still pour in the pool shock while going around the pool. This you do to evenly distribute the shock into the pool water.

Will low chlorine cause cloudy water?

Yes, it will.

The primary cause of cloudy water is low free chlorine levels. This indicates the presence of chloramines. The build-up of these chloramines is what causes the water to be cloudy. When the chloramine level is high, the free chlorine cannot do its job. This then results in a further build-up of algae and other organic matter. Hence, the water gets cloudy and murky.

How long after putting shock in the pool can I add algaecide?

Algaecides are chemicals that kill algae primarily. It is advisable to add them 3–4 days after shocking a pool. This is to enable the pool to get to normal levels of 1-3 parts per million of chlorine. If it is put in too early, the chlorine can render it useless.

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