How Do I Clear Up Green Water In My Pool?

On a hot summer day, nothing beats a clear, cool pool. Many homeowners, on the other hand, find that their pool looks a lot less appealing after a heavy rainstorm, with gloomy or even green water. Fortunately, with a little extra care, you can quickly restore your pool's water to its original state, or even avoid clouding from occurring in the first place. Read on for advice on how to preserve and clean your pool after a rainstorm so that it stays swimmable in the summer.

Why Do I Have a Green Pool? 

There's only one explanation why the pool water turns from a lovely shade of blue to a sickly green: pool algae. If the algae is a soft shade of green, it has just recently begun to take hold. A darker green, on the other hand, suggests a more severe issue.

When the pool's sanitizer levels are too low, algae grows. If you haven't been checking and balancing your pool water, or if you aren't using enough chlorine, bromine, or whatever sort of sanitizer you use, you're basically inviting algae to come in and make itself at home.


How to fix the green pool


1. Ensure that the water level in your pool is right.

Many pools drain excess water on their own, but if yours doesn't, you'll need to drain some water to get down to the correct amount before rebalancing the chemicals. To bring the water back down to about the middle of the skimmer float, open the drain, backwash the sand filter, or follow whatever technique is appropriate for your installation.


2. Brush the pool walls and floor. 

It's best to use an algae brush instead of your usual pool brush for this mission. Since algae is tough and stubbornly clings to the pool's surfaces, a heavy-duty brush is superior to soft nylon bristles for extracting it.


Scrub the pool walls, deck, stairs, and any other surfaces that have algae sticking to them with the brush. You might be asking, why don't you brush the pool before vacuuming it? You don't want to sweep up the algae, do you? No, it's not true. You don't have to. You want to get rid of the algae, and you'll need to do it when it's still in the pool.

3. Test the pool water.

When you've checked that your pool has the right amount of water, check the pH, total alkalinity, and calcium hardness levels to see if the water is safe to swim in. Heavy rains dilute the chemicals and can transport particulate matter from the air, increasing or lowering the pH of your pool. It's a good idea to add a little extra free chlorine, particularly if there were leaves or other organic debris in the water.


Your pool should usually fall within the following ranges, but consult your manual for precise instructions:

  • 100-150 ppm total alkalinity Protects from pH spikes by acting as a shock absorber.

  • pH range: 7.2–7.6 Irritation occurs when the temperature is too low. Calcium scaling occurs when the pH is too high.

  • 180-220 ppm calcium hardness Pools with concrete or plaster linings benefit from a neutral pH.


4. Use chlorine to destroy algae in your pool.

Killing the algae is the most critical step in clearing a green pool. Pool shock has a high chlorine content that destroys algae and sanitizes the pool. Use a shock that contains at least 70% usable chlorine and shock the pool twice for the best results. You must use chlorine shock to destroy algae, even though you usually use non-chlorine shock.


5. Filter the water and start the pump.

Check that the water can move through all of the circulatory equipment properly and that the filter pressure is natural. Allow the machine to run for a few minutes after you've achieved good circulation and filtration before going for a swim. The length of time it takes for the equipment to fully clear the water depends on the type of filter you use, which can range from a few hours for diatomaceous earth filters to several days for sand filters. Replace paper cartridge pump filters on a daily basis as a rule of thumb. Wash the filters with a hose and soak them in a bucket of white vinegar or bleach overnight to prolong their life.  If you use a sand filter system, be sure to perform a back flush according to the manufacturer’s recommendations.

Do You Need a Pool Cleaning Service You Can Trust?

Cal Pool Care delivers quality pool cleaning services to clients in the Tri-Valley and surrounding areas by providing them with the professional care they deserve. Great service begins and ends with experienced and friendly professionals, which is why we put so much consideration into selecting only the best to join our team. We complete projects efficiently and on schedule, and go above and beyond to form lasting relationships with our clients. Our service formula for success is consistency "same day, same time, same tech.” We offer weekly swimming pool maintenance and cleaning services. Cal Pool Care services pools, spas, and will ensure your fountains, water features and hot tubs are clean alongside regular pool service. Contact us today to schedule your first service!