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How to Lower pH In Your Pool (3 Easy Methods)

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Owning a swimming pool comes with plenty of perks, but it also requires a maintenance schedule that can be frustrating if not followed regularly.

You’ll have to learn how to lower pH in your pool, in order to maintain the water’s proper pH level at all times. 

If it becomes unbalanced (which can happen quite easily), it can create a host of problems for your pool and anyone who enters it.

When is pH too High? 

pH is the level of acidity in your pool’s water.

This acidity needs to be balanced. Too much causes problems as the water becomes alkaline, and too little causes problems as the water becomes acidic. 

The pH scale measures from 0 to 14, and the ideal reading you want to keep you water at is between 7.4 and 7.6. 

Some pool owners use a wider range of 7.2 to 7.8 for a bit more leeway, but a pH level of 7.5 is what you should always be aiming for. 

Why High pH is a Problem 

High pH over 7.8 means your water becomes basic, or alkaline. The issues this type of water presents are numerous:

  • It’s bad for your skin: Ever gone for a swim and come out with burning eyes, and itchy skin? That’s one giveaway of a high pH pool. Minerals as well as other contaminants attach to your body to cause this unpleasant feeling. You may also experience rashes, a stinging nasal cavity, and dried out but ‘sticky’ feeling skin.
  • It’s bad for your pool: High pH can cause scale issues. Water scaling occurs when the calcium in it combines with carbon dioxide to create calcium carbonate. This leads to a coating of scale all over your pool surfaces – from the walls to the pipes – and it’s especially present at the waterline where it can collect dust and dirt.
  • It’s bad for your pool equipment: A high pH can affect your pool’s operating equipment. This includes the pipes and filters, which can lead to equipment inefficiency and failure. Replacing equipment might be your only option if parts get damaged. 
  • It increases chlorine demand: Chlorine consumption is increased in a high pH pool. For reference, if you have a perfectly neutral pool, a single dose of chlorine will provide you with 80% concentration. If your pH level is slightly alkaline at 8.0, you’ll need 4 doses of chlorine to reach 80%.
  • It makes your water cloudy: A dead giveaway of pools with a high pH level is if the water turns from crystal clear to cloudy. This happens because high pH affects how the chemicals in the water interact, leading to improperly dissolved calcium (which adds a hazy look).

Why Your pH Level is too High 

It’s important to understand that a pool’s pH balance is fragile and can be easily swayed.

If you’ve tested your water and the results show a high pH level, the culprit may be any of the following:

Your Total Alkalinity is High

Total alkalinity refers to the neutralization of acids and bases in the water. This is important as it works to stabilize the pH level, which in turn, affects the functionality of your pool.

The ideal range of alkalinity is between 80 to 120 ppm (parts per million).

High total alkalinity is a common issue and there are steps you can take to reduce its level.

If left unchecked, it causes a chain reaction of events that will spike the pool’s pH level, leading to potential pool damage and skin irritation issues for those who swim in it.

When your water’s alkalinity is too high, it needs to be lowered. This is usually done by adding muriatic acid.

You Recently Shocked Your Pool

Shocking your swimming pool refers to the process of adding chemicals – usually chlorine – to stabilize the pH level. 

Shocking breaks up combined chlorine – killing algae, bacteria, and other pathogens – and it rapidly increases your chlorine level.

Combined chlorine (chloramine) is essentially chlorine that’s bound to ammonia and nitrogen. Translation: it’s an ineffective sanitizer when in this state. 

Adding shock breaks up the combined chlorine and creates an increase in free chlorine. This increase can spike your pool’s pH level. 

Pool shock is available in both chlorinated or non-chlorinated versions. If your pool already has a high pH level, using chlorinated shock will only make things worse.

You Have an Algae Problem

While your pool has a myriad of chemicals and sanitizers, algae can still bloom and cause your pH level to rise.

Algae is naturally occuring and is always in the water. Blooms are the result of inconsistent chlorine levels, unbalanced pH/alkalinity levels, poor water circulation, and poor filtration.

In addition to being an eyesore (and generally kind of gross), algae can damage your pool. Thankfully, there are products like algaecide which are highly effective in getting your algae problem under control quickly.

You Used a pH Increaser

A pH Increaser does just what you’d expect – it raises your pool’s pH level. Spiking your pool’s pH level by adding an incorrect dose is a common mistake.

Also known as pH Up, it’s composed of sodium carbonate (soda ash) or sodium bicarbonate (baking soda).

Baking soda is mainly used to raise a water’s alkalinity, but it also will cause the pH level to rise.

You Have a Saltwater Pool

Saltwater pools aren’t immune to high pH levels. In fact, they can be more susceptible due to their chemical makeup.

Sodium in saltwater pools combines with hydrogen and oxygen molecules, creating a high pH byproduct called sodium hydroxide. If your pool isn’t being regularly maintained, it can easily cause the pool’s pH level to skyrocket.

How to Lower pH in Your Pool 

Lowering a pool’s high pH level has a bit of a reputation for being difficult.

However, by adding acid with pH Reducer (or pH Minus), you can bring it back into balance. 

1. Use Muriatic Acid

Also known as hydrochloric acid, you should always use an abundance of caution when using muriatic acid. Colorless and pungent, this acid can cause skin burns, eye damage, as well as lung and nose lining irritation if inhaled.

Sounds like a great thing to put in your pool, right?

Well, experts unanimously agree it’s the best way to lower your pool’s pH level. 

Additionally, at the end of pool season, it can be used to clean stains, dissolve calcium build-up, and kill mold and algae.

After adding this acid, you should wait between 3 and 5 hours for it to fully dilute before going into the pool.

Pros:

  • Cost-effective
  • Lowers pH balance quickly
  • Available in a safe, powder form

Cons:

  • Liquid version can be tricky for pool owners to use
  • High degree of caution needed when using
  • May require medical attention if used improperly 

How to Use Muriatic Acid (Step-by-Step)

  1. Suit up in protective gear. This means fully covered clothing, gloves and goggles.
  2. Test for pH and alkalinity. Ideal levels are 7.4 – 7.6 (pH), and 80 to 120 ppm (alkalinity). If levels are too high, move on to step 3.
  3. Determine the amount of muriatic acid you’ll need to add. The manufacturer’s instructions will help you figure out this amount.
  4. Method 1: Turn off the pump system, and slowly pour the acid into the deep end of the pool. You can then turn the pump back on so the pool can circulate the acid.
  5. Method 2: Pour the acid near a return jet and the pool will circulate it.
  6. If you have an above ground pool, you’ll want to add the acid in a few spots and manually circulate the water while wearing gloves.
  7. The acid should be fully circulated after a few hours.
  8. Retest and repeat this process as needed. 

2. Use Sodium Bisulfate

A more mild acid than muriatic acid, sodium bisulfate is a dry acid that usually comes in granular powder form. 

While this makes it a little easier to use, you should still practice extreme caution around it, as it can damage your skin if you’re not careful. As sodium bisulfate is a powder, it’s recommended to not use it on windy days for safety reasons. 

Pros:

  • A bit safer than muriatic acid
  • Powder form makes it easier to use than liquid acids
  • Easy to add to the pool

Cons:

  • More expensive than muriatic acid
  • High degree of caution needed when using
  • Can cause damage to pool and skin if used improperly

How to Use Sodium Bisulfate (Step-by-Step)

  1. Suit up in protective gear.
  2. Test for pH and alkalinity.
  3. Determine the correct amount of sodium bisulfate to add by following the manufacturer’s instructions.
  4. Pour the acid near a return jet so the pool can circulate it. Do not add it to the skimmer!
  5. Above ground pool owners will need to add the acid and manually circulate the water wearing protective gloves.
  6. The acid should be dissolved after 15 minutes, but full dispersion will take 3 to 5 hours. 
  7. Retest and repeat this process as needed. 

3. Use Sulphuric Acid

While it’s a cheaper option than muriatic acid or sodium bisulfate, and will succeed in lowering pH levels, sulphuric acid is more of a last resort due to its hazardous nature. It’s been known to add sulphates and Total Dissolved Solids (TSDs) to pool water, which can be extremely hazardous if levels get too high.

Pros:

  • Cheap
  • No overpowering scent
  • Efficient in lowering pH and alkalinity

Cons:

  • Adds hazardous sulphates and TSDs
  • Dangerous to use
  • Can burn skin and corrode stainless steel

How to Use Sulphuric Acid (Step-by-Step)

  1. Suit up in protective gear and test for pH and alkalinity.
  2. Measure the correct amount of acid according to the manufacturer’s instructions.
  3. Method 1: Turn off the pump system, and pour the acid into the deep end of the pool. Turn the pump back on and the pool will circulate the acid.
  4. Method 2: Pour the acid near a return jet so the pool can circulate it.
  5. Above ground pool owners will need to add the acid and manually circulate the water wearing protective gloves.
  6. After 3 to 5 hours, retest and repeat these steps as needed.

Keeping Your pH Balanced 

Now that you know how to lower pH in your pool, let’s talk about how to keep it in check.

Test Your Water Regularly

Testing your water should be done at least once a week. This is because the pH level is extremely delicate and a drop or spike can easily occur – when someone goes in the pool, when it rains, even when the outside temperature changes!

There are 3 types of kits you can use to test for pH – test strips, liquid kits, and digital kits. All are easy to use and will return easy to read levels when testing water samples.

Keep Your Pool And Equipment Clean

Swimming pool water needs regular treatment to stay clean. An improperly treated pool will cause the pH balance to fluctuate, and a host of issues to take root. 

This can be anything from mineral build-up, to cloudy water and algae blooms. Not only will the water be affected (and hard to regain pH balance), but so will the pool’s filters and pump system. 

Shock Your Pool to “Reset” Everything

Pool shock can be a good way to “reset” your pool to a balanced state. As it contains high levels of chlorine, shocking will help destroy bacterias and algae that may have taken up space in your pool.

Some pool owners even shock on a regular basis as a preventative measure.

What Goes Up, Must Come Down. 

By now you should have a good idea of how to lower pH in your pool. 

While the best method is to keep on top of things and regularly test your water, it’s not always that cut and dry.

Knowing how to properly manipulate your pool water chemistry levels will allow you to swim in perfectly balanced water every time.

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