How to Fight Algae in Your Pool


How to Fight Algae in Your Pool

The benefits of having your own swimming pool are numerous, but not without responsibility. Controlling the growth of algae is a common challenge. Algae can turn your shimmering blue pool into a murky, discolored, and unhealthy swimming option.

As our North Texas weather continues to warm ups, your pool’s water quality may change and conditions conducive for the growth of algae may result. There are four main types of algae: green, brown, black, and yellow algae (sometimes called mustard algae.) While it is fairly straightforward to deal with green algae, the other types can sometimes present more of a challenge.

green swimming pool

Types of Algae

Green Algae

If your pool looks green and murky, you’re dealing with green algae. Green algae floats in your pool water, causing your pool to appear murky. A problem with green algae is frequently a result of insufficient sanitizer and/or circulation in the swimming pool.

Green algae will originally present as a cloudiness in the pool. As the algae continues to grow unhindered, the water quality will deteriorate and ultimately you will not be able to see the bottom of the pool. For the sake of safety and to prevent any increased risk of drowning, it’s important to deal with water clarity as soon as you notice this problem.

During the warm and sunny summer months, green algae spores are very common. A problem with green algae will develop if the pool’s chlorine levels are not maintained. Less frequently, green algae can contaminate your pool if toys, floats, or unwashed swimwear that have been in a river or lake are brought into the pool. It is very important that your pool maintenance company cleans their equipment after cleaning a pool infected with algae, or the algae spores can be spread from one client’s pool to the next.

High levels of chlorine and a good algaecide will typically kill the algae easily and quickly. After the pool has been properly treated, the filtration system should run continuously in order to capture dead algae debris and clear the water. A water clarifier can be added to make the clearing process even faster.

Black Algae

Black algae isn’t usually seen in the water of your pool, but on your pool’s plaster areas. It tends to develop first in the pitted area of the pool where the plaster has been etched or where calcium deposits have developed. Because water doesn’t circulate well in these areas, they are ideal locations for black algae to thrive. It can be challenging to treat this type of algae because of its ability to grow into the plaster and form a protective layer over itself. Black algae is often a problem in plaster pools where the surface has deteriorated, such as near lights, ladders, or broken tiles.

To control black algae, it will be important to maintain a higher ppm of chlorine and keep the phosphates under 200 ppb. An algaecide specifically formulated for black algae, such as Silvertrine, and brushing the pool will be needed, as well. It will also be very helpful to backwash the pool and vacuum any remnants of the algae to prevent it from re-infiltrating your pool’s filtration system.

Yellow/Mustard Algae

Mustard algae has a reputation the most difficult algae to remove and is more common in the southern states of the country, including Texas. Often mistaken for green algae or pollen, this type of algae is very resistant to even high chlorine levels and is able to thrive even in a chemically balanced pool. If the walls of your swimming pool have been brushed and the dirty appearance of algae or pollen seems to come right back, the problem is likely yellow algae.  It can be introduced to your pool via pool tools, inflatables, or swimsuits that have been in lakes or ponds, but it can also be introduced by wind, rain, or equipment used in other pools.

To successfully combat yellow/mustard algae, you will need to to choose an algaecide or chlorine enhancer designed specifically for it. Sodium Bromide will kill yellow algae efficiently, but the algae can easily return.  Combining the use of a chelated, broad-spectrum algaecide with keeping the phosphate levels in your pool under 200ppb is the best way to protect your pool on a long-term basis.

Brown Algae

Brown algae is actually a type of yellow or mustard algae, rather than different strain, and is rather rare. It typically develops in pools with poor chemical balance and lots of shade. It can be somewhat resistant to chlorine. However, high concentrations of chlorine can kill it.

Shocking the pool can kill brown algae, but care should be taken prior to thoroughly brush the sides and bottom of the pool so that the chorine will be able to access it well. Before shocking, you should also adjust the pH, as alkaline water renders chlorine less effective.

The importance of pool maintenance

Regular maintenance is crucial to prevent algae growth. Your swimming pool should be maintained both chemically and physically by brushing, vacuuming, cleaning the skimmer, and cleaning out the pump baskets regularly. This helps ensure that the environment is less hospitable to algae. Always be sure that the pool and spa filters are cleaned thoroughly before addressing an algae problem

During our North Texas summers in particular, it is important that pool’s chemical levels are in balance and that the pump and filters run 8-10 hours a day. Algae treatments are not as effective if the swimming pool and spa water are not properly balanced and being filtered and circulated well. Testing early in the season can be key to prevent algae bloom. You’ll want to be sure the phosphate level does not exceed 200ppb at any time.

Additional help with algae control

Two options for limiting chlorination and the need for chemical additives are pool ionizers and ozone systems. Ionizers are copper or copper/silver systems designed to reduce the need for adding chlorine. An inonizer utilizes a micro-processor control box to send a signal to electrodes that are made of natural minerals, causing these electrodes to then release ions, helping to eliminate algae in your pool. Ozone systems help control algae bloom by eliminating chlorine residues, bacteria, molds, and viruses. Ozone systems reduce algae by using ozone gas to sanitize the pool via oxidation of negative waste material. The use of ionization systems and ozone systems can be combined for powerful algae control that can keep your swimming pool clean and clear of algae all summer long.

Summer is just around the corner, so make plans to prevent algae bloom in your swimming pool now. To keep your pool’s chlorine, PH, and total alkalinity properly balanced:

  • Run your pool 8-10 hours a day in warm weather
  • Brush walls, tiles and steps of pool regularly to get any algae spores off of surfaces
  • Add copper-free algaecide plus shock (Cal-Hypo) proactively at the first sign of algae
  • Call Executive Blue Pools for weekly pool maintenance if you don’t have time to maintain your pool properly

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