What Chemicals Are Added to  the Pool to Make it Blue?

What Chemicals Are Added to the Pool to Make it Blue?


We all want our swimming pool to be sparkling clean and blue.  This isn’t always the case.  Sometimes we have unsightly algae. We may have cloudy or murky water.  We may have visible debris and particles floating in the water.  In order to have a blue swimming pool, we have to have good water chemistry.  This requires us to add chemicals to balance it.  Here are some chemicals you may find yourself needing to use.


Whether your swimming pool is a traditionally chlorinated pool, a salt pool or a bromine or other special sanitizer, we need to have our levels within range.  If we do not have enough sanitizer in the water, we can be prone to algae.  Low sanitizer can also make the water look cloudy.  Sanitizer is also required to keep your swimming pool water safe for the swimmers.  We don’t want anyone getting sick!

Muriatic Acid/Dry Acid

Sometimes when we test we may find that our pH is too high.  Don’t go adding anything yet!  We also need to test our alkalinity.  When the alkalinity is low, it causes the pH to be unstable and “bounce” around.  Since pH and alkalinity are on what is known as a buddy system, it is not uncommon to find these levels high together.  If this is the case, you will need to lower them using either muriatic acid or dry acid to get them into the desired range.  Low alkalinity has been known to cause cloudy water.

Calcium Chloride

A lot of places have “hard water”.  What this means is the source water has a calcium level that comes out of the tap higher than our goal of 200-400 ppm.  If you are refilling your pool or have a leak, you may find your calcium level is lower than the desired range.  In this instance, you would need to add a calcium elevator known as calcium chloride.  Don’t add too much because the calcium will creep up over time.

Alkalinity Up

If we find our alkalinity low like we briefly discussed before, we will need to add sodium bicarbonate to raise it to an acceptable range.  By raising our alkalinity we may also find that it pushes our pH up and sometimes out of range.  We would then adjust accordingly with muriatic acid or dry acid to get our pHand alkalinity back into their buddy system.  Remember, your alkalinity acts as a buffer to help keep the pH stable.  


You may have a green pool and are doing a full blown algae treatment,  This includes pairing an algaecide with sanitizer, running the pump and cleaning the filter.  Not fun.  To avoid this, you may want to include a maintenance dose of algaecide in your weekly routine.  While keeping the water balanced is key to a blue pool, having a little insurance policy never hurt anyone.

Want to get rid of the mustard algae in your pool? Learn more here.

Phosphate Remover

Phosphates are anything organic such as leaves, pollen and anything organic.  Phosphates are food for algae.  By adding a weekly phosphate prevention product, we can keep low phosphates low.  This means if your water becomes unbalanced and algae starts to grow, it will slow down the bloom because we have cut off the food supply.  Phosphates already high?  I suggest doing a phosphate treatment to get them back under the high limit and then starting a weekly regime.


There are two ways clarifiers can work.  Some brands literally eat away at the particles that are too small for your filter to pick up.  The other works by clumping the particles together and allowing them to become large enough for your filter to remove them.  You definitely want to do this after an algae treatment as dead algae can cloud up the water because the particles are small.  Make sure it is not a chemistry issue before jumping to a clarifier or it will be pointless.

Proper Circulation

While this is not a chemical, it is key to making your chemicals work.  We absolutely need to make sure our pump is running long enough and that our filter is clean.  This allows the chemicals to mix and thus become effective.  It also allows dirt and debris to get snagged in our swimming pool filter.

If you are not running your pump long enough or running it at night to “save money” you are making more work for yourself.  You will constantly be battling algae and cloudy water.  If you have a single speed pump you know how expensive they are to run.  I suggest upgrading to a variable speed pump, which is energy efficient and will cost you way less to operate.  

Think you can’t afford a variable speed pump?  Think again.  The American made, household name of BLACK + DECKER makes a variety of horsepowers that are available for about half of what your local pool store will be selling other brands for.  Check them out here. 

They even make an above ground model.  See you poolside!

Related articles:

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Chlorinate Your Pool in Three Easy Steps