Do I Really Need To Use Algaecide In My Swimming Pool?

Algaecides and algaestats treat and prevent algae growth in pools and hot tubs and are important tools to keep in your pool care arsenal. While the chlorine you use for regular pool maintenance and water sanitization does have bactericidal and algaecidal properties, the addition of pool algaecide will enhance and prolong the effectiveness of the chlorine and can act as a valuable backup to the anti-algae effects of regular chlorination. If algae are present in your pool despite your regular pool care routine, which can be indicated by brown, green, blue-green, black or yellow areas on the walls of the pool or an algae bloom in the water, then pool algaecides are definitely in order. The most common forms of algae are extremely resistant to treatment with chlorine; therefore, algaecides will be necessary to rectify the situation and return your pool to the clean, clear, refreshing haven as intended.

The chemistry of algaecide is pretty complex since there are more than 46 species of clear water algae that exist today. Some types of algaecide work better on certain species of algae that others. Algaecides are primarily algae inhibitors that work in conjunction with pool chlorine to help control and prevent algae growth. Planktonic clean water algae float on the surface of pool water while other types will attach and grow onto the pool floor or sides. Many factors affect the development and growth rate of algae. Water temperature, sunlight, pH, mineral content and chlorine residual of the pool water will all help to encouage algae development if the water is not balanced or the potential for problem addressed. Algae can be introduced to the pool by rain, falling leaves, wind or even bathing suits transfering algae from one body of water to another. 

Because wind and rain is constantly introducing algae spores into your pool water, prevention is the key component to managing algae concerns before they become a problem. Inadequate pool water circulation and pool care treatment is another contributory cause to pool algae development. Algaecides and algaestats are a good idea if the conditions where you live favor algae growth, such as areas that routinely experience high temperatures, large amounts of direct sunlight or heavy rain. If you find that for what ever reason, you just do not seem to have the time to take care of your pool water as you should and as we advise, then algaecides should be added to your pool care. Once algae is visible in your pool, the algae colony is already well established, which can quickly cause your pool to become dangerously slippery and can begin to increase the pH level significantly. As the pH rises the sanitizer becomes more ineffective. You can avoid this by incorporating algaecides and algaestats into your pool care routine.

What is the difference between pool algaecides and algaestats?

Algaecides are used to kill algae; whereas, algaestats are a proactive treatment that is used to prevent the growth of algae. In many cases, the difference between algaecides and algaestats is simply the dosage strength of the chemical formula used for treatment. For example, algaestats are recommended to be used once per week to inhibit algae growth will likely be similar to the chemical formula of an algaecide that is a concentrated strength to kill existing algae. There are many different types of algaecides and choosing the right one for your pool may seem to present a challenge.  Although the is no test for algaecide levels in the water, following the proper use and manufacturer directions to maintain a working algaecide level in the pool is an effective deterrent to algae development.

Which Algaecide Shoud I Use?

Which algaecide will work best for your particular situation depends on the type of algae growth you are experiencing. For example, most algaecides are effective against green algae, but black algae may require an algaecide specifically formulated to treat this resistant type. Below are brief descriptions of the four primary types of algaecides commonly used to treat swimming pool algae. There are also strong algaecides blended with water clarifiers to help your filtration system remove dead algae from the water. The most common type of algaecide is called quaternary ammonium formulas or "Quats". However, quats cause foam to form on the pool water surface due to their ability to also decrease water surface tension. Foaming is perfectly normal for quats and the foam will have a short presence in your pool. These are available in different concentrations and are very effective algae inhibitors. Another type of algaecide that does not produce foam has a polymer additive to prevent it. These are called "poly-quats". The algaecide that we recommend most for any pool type that is best for your weekly pool care routine is Blue Wave Halt 50 algaecide. There are still other types that are more specific that have silver, copper or magnesium added to them to destroy those hard to kill algae such as pink slime, mustard or black algae. 

What the differences are between Algaecides:

Copper Algaecide
Copper algaecides kill algae through suffocation and metabolism disruption and are an effective treatment option for most types of algae. They are highly effective when used to treat green algae or mustard algae and do not have the foaming issues associated with quaternary ammonia algaecides; however, if not used at proper levels, copper-based algaecides can cause staining on some concrete pools. Most copper algaecides include a chelating agent to prevent this. Copper algaecide is a good choice for use in vinyl liner pools. You should not use a copper algaecide with a biguanide based sanitizing system such as Baquacil® or SoftSwim®.

Quaternary Ammonia Algaecide
Quaternary ammonia algaecide, also called Quats, are the most cost-effective product to use as both an algaecide and an algaestat. Effective in both capacities, quats work best against green algae and kill algae growth through cellular membrane disruption. While quats do not case staining, foaming can occur, especially when not used properly. If you have experienced any metal staining in the past, you should use a quat or polyquat algaecide to treat your swimming pool.

Polyquat Algaecide
Polyquat algaecides are a highly effective treatment option for all types of algae and do not have the staining issues of copper algaecides or the foaming issues of quats. Polyquats are stronger algaecide formulas that kill algae through cellular membrane disruption, similar to quats, but are composed of longer molecular structures. This type of algaecide is safe for use in any pool yet tends to be more expensive and more effective than other options. If your pool is already algae infested, shocking the pool with a large amount of chlorine shock is still the first choice and then when the chlorine level has returned into the normal range, the algaecide treatment will be more effective.

Black Algaecide
Black algaecide is specially formulated to destroy black algae (dark blue-green algae), which can be very resistant to chlorine and other algaecides and algaestats. These algaecides are generally a proprietary blend of a copper-based algaecide and a quaternary ammonia algaecide and are highly effective in both preventing and destroying black algae. They work through a combination of cellular membrane disruption, metabolism disruption and suffocation. Black algae forms in layers within the small crevices of concrete and plaster finished pools. Once established, black algae are tough to get rid of because chlorine alone has little effect, and on only the surface layer of the algae. Using a stiff brush, you must first break through the algae surface layers for any algaecide or chlorine treatments to be effective and then you need to maintain higher chlorine reading (3.0) and lower the pH to 7.2 for a period after treatment to destroy this form of algae.

As you can see, each formula of pool algaecide has a specific purpose and treats certain types of algae. Always buy a concentrated algaecides to treat or prevent the algae your pool is prone to experience. Do not buy gallons or half gallons of cheap algaecides typically available at mass merchants. Most of there products are very weak quaternary ammonia formulas and not a good value.