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Tips for preventing excessive algae growth in pools

The darker the colour, the more extensive the algae outbreak, especially with green algae.
The darker the colour, the more extensive the algae outbreak, especially with green algae.

The proper treatment

Determining which algaecides to use comes down to what type of algae is present. Secondary factors to consider are personal preference, affordability, and availability. This will help professionals select the appropriate treatment to help clarify the pool water. As mentioned, certain treatments are better suited for particular species of algae.

It is also important to establish how much algae is in the pool. While there are some who may be reading this article poolside and are able to assess the situation first-hand, there will also be several others flying blind behind a counter, solely leaning on the words of a likely embarrassed customer. Many consumers may feel they did something to cause the excess algae growth, so they could possibly diminish the severity of the issue.

For the customer who is seeking for an immediate solution, it is essential to ask more questions than just, “How does the water look?” Professionals should inquire further about the amount of algae and, more specifically, the colour of the pool water. Typically, the darker the colour, the more extensive the algae outbreak, especially with green algae. If the pool has algae and the water is clear, finding out what percentage of the pool has the algae, what colour it is, and its locations will be important in determining treatments.

In many cases, when clearing large amounts of algae, there are two actions that need to occur prior to adding an algaecide. The first is to address the pH, if applicable. Usually, when the water has been overrun with algae, the pH needs to be corrected. This is because it will often climb as algae accumulates, and most algaecides—other than ammonium sulfate—will function better in a more neutral environment. The pH will also need to be adjusted for the next step, which is to “shock” the water with a chlorinating product. It is essential to get a lot of hypochlorous acid (chlorine’s killing agent) out of the chlorine that is added. One can even make the case to have the pH temporarily go slightly below 7.2, toward 7.0, to produce more hypochlorous acid. Ultimately, the best practice is to follow the label directions for any product.

Another precursor, prior to applying treatments, is the mechanical removal of any presence of growth. If there is less to treat in the water, then whatever is used to help remedy the pool will go further. Those working in the field will have to find out the correct order and balance to maximize their time. Whether they are doing the heavy lifting or giving advice, the best practice is to remove the matter out of the pool altogether. Ideally, using the pool’s vacuum system or a standalone vacuuming system with a fine mesh bag will help clear up the water along with any buildup. Since time is essential to everyone, at the very least, a thorough brushing of all surfaces along low circulated places (under the ladder, corners, etc.) is encouraged to have all the growth floating freely around the water. In theory, all this matter should take on the treatment products in the water, for a more successful kill rate.

The finishing touch

Any effort to successfully turn a pool from a haven of growth to an inviting oasis will involve circulation and filtration. Circulation will ensure all the treatment products meet with the algae to help ensure its demise. Once the algae is killed, the filter will help clear it out of the water. However, it can easily get overwhelmed with dead particulate during the pool’s recovery, so rinsing or backwashing it may be necessary to speed the clearing process along. Some of this particulate can be very fine, so it may be helpful to use a supplement such as a clarifier or an enzyme. These are not a necessity for success, but they could help, especially for sand filters, as the media is not as capable of catching as
fine a particle size, compared to cartridge or diatomaceous earth filters.

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