Should You Use an Algaecide in Your Pool?

If we own a swimming pool, we have to maintain it.  It is a luxury item and requires a lot of upkeep.  We have to net it, brush it, vacuum it, clean out the baskets and maintain proper chemical balance.  But just what chemicals should you be putting in your swimming pool?  Let’s chat a bit about it, shall we?


The most widely used form of sanitizer is chlorine.  Chlorine comes in many forms.  We have liquid chlorine, dichlor, trichlor and calhypo.  Let’s not forget chlorine tablets!  Some people utilize a salt system.  A salt pool is still a chlorine pool, we just make our own using a process called electrolysis.  There are also alternative sanitizers such as UV and Ozone.  But these require a small residual of chlorine as well.  Bromine may be used in indoor pools or in spas.  

The purpose of sanitizer is to kill bacteria, germs and other dangerous stuff that hangs out in the water.  It also combats algae.  It is never safe to swim in a pool or spa without a proper sanitizer level as one could get really sick.


We also have to be mindful of our pH and alkalinity.  These two fields are on a buddy system.  This means that they usually go up and down together.  This is not always the case as alkalinity can get too low over time and if you have a water feature, it causes aeration, which raises pH, but not alkalinity.  Whatever the case, we need to adjust it accordingly with either dry or liquid acid if we have high levels and either alkalinity up or soda ash.

The purpose of adding these chemicals is to get our pHand alkalinity in the desired range.  For pH that is a 7.5 ppm.  For alkalinity, 80-120 ppm is deemed acceptable.  We want these fields in range to ensure our sanitizer is most effective.  Having these in range can also help prevent scaling.  It also helps protect your swimming pool’s surface, your plumbing and your equipment. 


These are products that you may or may not find yourself needing to use.  Water Clarifier helps clear up murky water.  Especially after an algae bloom.  There are many types of clarifiers.  Some make the particles larger so your filter can filter them out.  Some make the particles larger and drop them to the bottom of the pool so that you can vacuum them out.  Some simply eat away the particles, not adding anything to your filter.  The purpose of clarifiers is to get rid of those pesky small particles, giving you a clean, sparkling swimming pool.

Phosphate removers are a great addition to your weekly maintenance program.  There are products that can be placed in the skimmer weekly to keep low phosphates low.  There are also “solution” phosphate removers which remove high levels of phosphates.  Keep in mind you often have to do a filter clean after this kind of treatment.  My advice?  Keep low phosphates low.  Phosphates are anything organic that may get into the water such as leaves, flowers, pollen etc.  This turns into food for algae.  If you were to get an algae bloom, having a Las Vegas buffet laid out for it is no bueno.  But other than that, phosphates are only a problem, when they are a problem.  Make sense?

Stain and scale removers come in preventative options and removal options.  Some you pour into the swimming pool and it works within the water.  Some you manually apply to your tile line and scrub off.  Just like with phosphate removers, there are preventive and repair types of stain and scale removers.  

Pro Tip:  When refilling your pool with fresh water, it is advisable to include a stain and scale remover 

Metal sequestering or chelating products are also available.  If your tap water has a high metal content or you use a metal based algaecide, you can see this build up over time.  Copper is a big one.  If you ever see bright blueish purple staining or people are getting green hair, you most likely have a high copper content.  Anything over 3.0 is too high.  If you have poor water chemistry and have a low pH and alkalinity over an extended period of time, this can also cause metal in the water.  Where is it coming from?  Either your heat exchanger in your pool heater or on older pools, the copper piping.  Metal Gone products can be preventative or repair usage.


Ah, the age old debate about algaecide.  The truth is, if you have a perfectly balanced pool at ALL times, you shouldn’t need an algaecide.  Most people can’t boast this because, hey, life happens.  It is nice to have an insurance policy against an algae bloom.  There are many types of algaecide: quat, polyquat, silver based, copper based, and sodium bromide based.  Unless you are dealing with black algae, I am a bit scared of silver based products.  My preference is Yellowtrine, which is sodium bromide based.  It is safe for any vessel and requires only a capful or 2 a week , depending on the size of your pool.

Algae blooms.  When we get an algae bloom, we need to pair high doses of sanitizer with an algaecide to get rid of it.  If you need advice on how to kill algae in 24 hours, check out our other blogs.


You are probably thinking, “Hey!  Circulation is not a chemical!”.  And you would be correct.   But as your pool girl I would be remiss if I did not touch on the importance of proper circulation when it comes to pool maintenance.  

Pro tip:  Always add chemicals when the pump is on and allow adequate circulation after the product is added.

Regardless of the chemical, it only mixes and works if the water is moving.  My go-to statement is “Moving water is happy water”.  I always envision a pond and a stream.  A pond is green and yucky because it is stagnant.  A steam is clear because it is constantly moving.  Make sure you run your pool pump enough hours a day.  If you have an old fashioned single speed pump, this can get quite expensive.  I recommend to all of my clients to upgrade to an energy efficient, variable speed pool pump.  In some States, they are required by law.

If you were to go to your local swimming pool store and inquire about a variable speed pump, your jaw would drop at the price.  We are talking about a couple of grand.  Yikes!  I want to share with you that you can get a quality, American made, brand name Black & Decker variable speed pool pump for about HALF of those other guys.  Don’t believe me?  I am hurt!  Just kidding.  See for yourself here.  

So we have lots of chemicals we need to maintain our swimming pools.  Always follow the product’s directions and wear the proper PPE (Personal Protective Equipment) when handling chemicals.  Also, properly store your chemicals, allowing distance between incompatible chems.  And remember, It is better to PREpare than it is to REpair.  See you poolside!