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What Pool Chemicals Should Not Be Mixed

It's common knowledge that certain pool chemicals should not be mixed. Each type of chemical serves a specific purpose and mixing them can nullify their effectiveness or, worse, be dangerous.

Some of them are so reactive that you should even avoid keeping them near each other. There are numerous bad chemical combinations In this blog post, we will explore which pool chemicals should not be combined and why. By the end of this post, you'll be a pool chemical expert!

Is It Okay To Mix Pool Chemical Brands?

For most saltwater pools, it is ok to mix different brands of chemicals. However, it is ideal to stick to a brand that you feel you have had the most success with.

While many items are interchangeable as they offer the same active ingredient, some are inferior products due to their overall composition. The products we recommend you can interchange with confidence are buffer, stabiliser, liquid acid and liquid chlorine.

If you are using a different pool sanitation system, it is recommended you stick to the same brand. Ie, Poppits, AquaFresh and other chlorine-free sanitisation systems.

Can I Add All Pool Chemicals At The Same Time?

No. With the exception of salt, you should never mix any types of chemicals and put them together, not even close to each other.

Never want to mix acid with chemicals like stabilisers, chlorine and buffers. Salt can be added with acid. Due to the nature of the acid, its low pH will react with anything with a higher pH such as chlorine - similar to when you mix vinegar and bicarb soda (it bubbles and foams up).

After adding acid, you should wait 3-5 hours (depending on the size of the pool) and test your water before applying any further chemicals.

Liquid chlorine cannot be added with another chemical either (except stabiliser). Liquid chlorine for at least 8 hours before adding another chemical. Again, it is best practice to test first. Mixing acid and chlorine is very dangerous, it can combust and will cause very dangerous chlorine gas.

Bad Water Balance Combinations

If the chemicals in the pool water are imbalanced, you know that it can cause a variety of problems. Among bad water quality, scale buildup, and stains, there is a problem of insufficient sanitation. It can also create serious damage to your pool equipment and accessories, causing corrosion.

If You Have High Calcium Hardness and High pH in Your Pool

When you have this combination happening, you will most likely get cloudy water combined with scaling. You will notice the scales forming on both pipes and the pool surface. These buildups can be sharp and can cause scratches and tears on the swimsuits.

If Chlorine Levels Are Low and pH is High

This combination is perfect for an algae bloom. A high pH level is a perfect breeding ground for different kinds of algae. If the chlorine becomes low, they will seize their opportunity to bloom.

If Total Alkalinity and pH are Both Low

This combination will cause corrosion of steel, and copper. Acidic water is perfect for corroding your pool equipment and pool surfaces. But what happens when total alkalinity is high and pH remains low? Again you will notice more corrosion and you will find it very hard to raise the pH levels again.

If The Water In Your Pool Has Low Chlorine And Low Stabiliser Level As Well

We mentioned that the stabiliser acts like a sunscreen for chlorine and when the pool water is low on the stabiliser, chlorine gets destroyed much more quickly. You may start noticing that the water gets hazy, then cloudy and in the end, it gets totally green. Take a close look at your pool to see some warning signs that the pool water is low on chlorine and stabiliser as well.

Yet what happens when the water is high both on stabiliser and chlorine levels? This can cause some serious damage to softer and shiny pool surfaces. High stabiliser levels can cause problems with chlorine effectiveness. In that case, you can’t rely on chlorine testing because the results won’t be accurate.

High Chlorine Levels

Chlorine molecules and chloramines combined when there is no active stabiliser around can cause red eyes. Plus the pool will have a notable smell of chlorine.

Low Calcium Hardness

It can cause corrosion on your pool equipment. It is also really bad for vinyl pool liners and it can cause chemicals to be less effective.

What If The Pool Water Is High In Phosphates?

Phosphates are the favourite foods for algae and they can cause an algae bloom. They can enter the pool through various sources. When the phosphate levels are high, you need to get a remover.

Incompatible Pool Chemicals

There are certain pool chemicals that should never be mixed together. Doing so can cause dangerous chemical reactions that can be harmful to you and your pool. You want to get a healthy environment so you need to be careful with pool chemical applications.

If pool chemicals are added in the wrong order, at the same time or if you haven’t waited long enough between applications, it can cause some serious problems and imbalance. Always read the instructions carefully.

My (Bad) Chemical Romance

At all costs, avoid pool chemicals contacting each other. Never. Raw chemical reactions can occur even outside your swimming pool. Chlorine is safe for use but what happens when it is mixed with other chemicals and substances? Toxic gasses, and explosions… Chlorine can become a serious health and safety hazard if you don’t know how chemical reactions work.

Store all your chemicals in dry, dark places with proper ventilation and stable temperature. Keep them in their original containers and make sure that pool chemicals are sealed.

Algaecide and Chlorine Shock

Chlorine shock will not work well with chemical compounds from algaecide, causing polymer chains to be disrupted. It will completely ruin the algaecide in most cases. How to prevent this from happening?

Use the pool shock to kill all the algae and wait for chlorine levels to get back to normal. After that, the next step is applying algaecide. Make sure not to use too much or you will start noticing foamy water.

Enzymes and Chlorine Shock

Just like with algaecide, the chlorine will disrupt the enzymes and they will not do their magic. Wait until chlorine levels are back to normal and then add enzymes. Pool chemicals are expensive so make sure that you are not wasting your money because you are rushing the entire process.

The same applies to sequestering agents that are used for threatening scales and buildups. You should never add them at the same time with chlorine shock. It is recommended to wait for a few days after you applied the pool shock

Chlorine Shock and Metal Buildups

There are a few different things that can cause metal buildup in your pool, the most common being your water source or having poor water balance. When you have high metal levels, shocking the pool will rid them of the solution and make stains in your pool. Keep pH, total alkalinity and calcium hardness levels within range, and add regular treatments of a sequestering agent to prevent stains.

Chlorine Shock and Trichlor Tablets

Never, absolutely never pour dichlor pool shock into the pool through the skimmer if you have a chlorine feeder with stabilized trichlor tablets. The chemical reaction between these two types of chlorine can cause a fire or explosion that will burn your equipment and/or injure you.

Follow the instructions on your product label when adding shock to your pool and make sure you apply it evenly instead of concentrating it in one spot.

Muriatic Acid and Chlorine

When mixed, these two chemicals create a toxic gas that can be dangerous or even fatal if inhaled. Carefully read the product label and follow all directions to avoid causing an adverse reaction. Never add muriatic acid to the pool when chlorine levels are high. Never shock the pool immediately after adding muriatic acid to the water.

Stabilised Chlorine and Cyanuric Acid

One of the only reasons to need a stabilizer or conditioner in your pool is if either (1) it was just recently filled and levels are too low, or if (2) you're using chlorine that isn't stabilized. Stabilized forms of chlorine, like 3" trichlor tablets from your feeder, contain CYA. If you're doubling up on CYA, you'll quickly find that levels are too high and you'll need to drain and refill your pool to dilute them.

Combining ph/Alkalinity Increaser and Calcium Hardness Increaser

If you put in a Hardness Increaser too closely to a pH or Alkalinity Increaser, there's the risk of the two reacting badly and creating cloudy water or even small solids. This can easily lead to scale buildup.

Clarifier…Plus More Clarifier

Two negatives equal a positive? Well, wrong in this case. Some formulas of clarifiers behave as coagulants, while others have the opposite effect, acting as dispersants. To prevent excessive build-up of chemical levels in your pool and to keep your water at perfect clarity, we recommend that you wait 5-7 days before adding more clarifiers to your pool. It is also important to follow all instructions found on the product's label for dosing and application instructions.

In Conclusion

Never add chemicals at the same time. Whether you're balancing your pool's water, shocking it, or adding specialty chemicals, you should let the pump run for a set period of time before adding another chemical or retesting the water. The product label will provide detailed instructions for wait times before adding more chemicals or swimming in the pool. If you are not sure where to begin, make sure to consult the experts.

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