Pool Maintenance 101: How to Remove Algae

Your pool is without a doubt one of the most happening hot spots for the whole family, but it’s also an ideal environment for a big variety of less-than-desirable visitors. What are algae, exactly? This stuff is essentially a grouping of aquatic, plantlike organisms that love your pool water.

Algae come in a variety of different strains and colors, with the most common being green, but it may also be blue, yellow, or black. Some colors are more difficult to remove than others, which is why a one-size-fits-all method of pool algae removal isn’t always the best course of action.

With that being said, there are some tried-and-true steps you can take to eradicate your pool from this gross, slimy stuff, no matter if it’s dark green or mustard yellow. If your pool water appears to have a greenish tint, algae are likely the issue.

This stuff also loves dark spots and may grow along the walls of your pool or behind ladders, under the diving board, or beneath ledges. Periodically shocking­ the algae — or delivering a super-sized dose of chlorine and other chemicals — as well as brushing it away, are all effective ways to prevent it from spreading.

Find out your home's credit score

Check your home condition score to find out!

Check it out

What Causes Algae?

At their core, algae are oxygen-loving organisms. These living creatures are also a lot like your family in that they enjoy warm, sunny weather, and clean water. Algae spores will find your pool water through a wide range of methods: from rain, pollution, contaminated pool equipment, swimsuits, and other factors.

These contaminants lead to a less-balanced environment, which is extra-hospitable to algae. Algae reproduce fast, which is why you may see overnight algae bloom after a heavy rain or a pool party.

Algae grow in water that’s not properly sanitized. Most pools use chlorine and other sanitation mediums to remove bacteria that lead to the growth of algae. Algae are also more likely to grow in pools that don’t have a good circulation system. That’s why these icky little organisms tend to develop and spread in areas of the pool that aren’t in the direct line water flow.

Ensuring that your pool is well-sanitized and that the circulation system is running properly will help ward off gross algae. But first, you need to thoroughly test and monitor your water. 

Read more: Salt water pool vs chlorine pool review

Step 1: Assess the Issue

Before you develop a plan to treat pool algae, consider investing in a meter that will help you determine your pool’s total dissolved solids (TDS). Contaminants, such as salts and minerals, boost water’s conductivity, which can suppress the effects of chlorine.

A conductivity meter is a simple way to spot-check your TDS levels. If your TDS levels are high, there’s a good chance that they’re hindering your sanitization agents and leading to the development of algae.

A pool conductivity meter will measure how many dissolved solid materials — such as minerals, metals, and salts — are contaminating your water. So, what is a good TDS level in your pool to prevent algae?

First, it’s important to note that a good TDS meter will measure in parts per million (ppm). According to the Association of Pool and Spa Professionals (APSP), the maximum TDS in your pool should be between 2,000 and 3,000 ppm, or 1,500 ppm greater than the TDS at the time the water was added.

Read more: Saltwater pool maintenance

Step 2: Brush the Algae Away

Regularly brushing the walls, stairs, and the bottom of your pool is an effective way to help prevent the rapid growth of algae. Before you add any chemicals, you want to make sure that you’re working with clean surfaces that will make your shocking agents more effective.

Brushing away algae essentially breaks the skin of the organisms and loosens the algae so it moves into the water of your pool. Once it’s within the water, the chemical sanitizers will be better equipped to remove contaminants and bacteria that cause algae.

Read more: How To Take Care Of Your Swimming Pool Equipment?

While this may seem like a relatively simple process, there is some nuance to properly scrubbing the pool. You need to make sure that you have the right kind of brush — with the right kind of bristles — so that you’re sloughing away even the most microscopic particles from the surface of your pool without damaging the pool’s surfaces.

If possible, refer to your pool manufacturer for brush recommendations. A general rule of thumb is to use nylon pool brushes on your vinyl and painted concrete and stainless steel, and nylon combination brushes on unpainted concrete.

Read more: What is pool shock treatment

Step 3: Shock the Algae

As previously mentioned, shocking your algae is an effective method to warding off stubborn algae that tends to spread and grow in dark areas of your pool. Choose a high-concentration chlorine or another sanitizing chemical and treat your pool in doses, with a recommended amount of about three shocks over a 36-hour period. Although shocking your pool water isn’t an immediate method to treating algae — it can as little as three days or as long as a week — it’s one of the most effective options for treating difficult black, yellow and green algae.

As a general rule of thumb, the Centers for Disease Control and Prevention (CDC) recommend keeping your chlorine levels between 1 and 3 ppm (with a pH of between 7.2 and 7.8) in normal conditions. However, when you’re using the shocking method, you should raise the chlorine levels to about 10 ppm.

Naturally, you should not allow anyone to swim in your pool until the chlorine levels have returned to normal. Test the water regularly using a pH water test kit to ensure that chlorine and pH levels are back to a safe ppm before inviting anyone to swim in the pool.

By following these simple steps, you’ll be well on your way back to crystal-clear water that’s free of algae and other gross contaminants that can make your water murky and inhospitable for your human guests.

Read more: Pool removal guide

Written by Phil Mcnamara. July 31, 2018

Phil is originally from California, where the need for water filtration equipment is vast. After college, he dove into the growing problem of clean water both nationally and worldwide. After many years in the industry, he found WaterFiltersFAST.com and aligned his knowledge of the industry with theirs to help educate and inform consumers. He is also an avid outdoorsman and tech enthusiast. An oxymoron for sure, but he makes it work.