While it’s not necessarily dangerous to humans, yellow algae in swimming pools are still unsightly and gross. Nobody is going to want to swim in a swimming pool that has ugly discoloration. Sometimes it doesn’t even look that bad – at least in the early stages. It can easily be mistaken as pollen or even sand. A mustard alga usually isn’t “slimy” either. Many pool owners don’t even realize they have it at first until it starts to spread.
And it can REALLY spread – not just around the pool floor and walls – but to equipment, toys, floats, and even bathing suits!
It is absolutely essential that you learn how to get rid of mustard algae before any overgrowth begins, because there is the possibility that it could begin harboring harmful bacteria such as E. coli.
Once it begins to grow, it’s very difficult to eradicate, and it could still come back again if you don’t start taking better care of your pool.
Step 1 – Clean EVERYTHING
If you suspect that you might have algae, the very first thing you need to do is clean everything that has touched the pool. This includes all equipment, toys, floats, beach balls, the ladder, and even bathing suits. Most of these can be cleaned with Clorox or white bleach. Spray down the surface and wipe the item down with a clean cloth. As for the bathing suits, they should be thoroughly washed with color-safe bleach.
A robotic cleaner isn’t going to be enough to scrub the algae since it can grow in the little nooks and crannies of the surfaces. This is something that you have to do manually with a brush. Don’t forget to scrub beneath the steps on the ladder and around the fixtures and gaskets. Ideally, the algae will settle on the bottom. From there, vacuum the bottom using the “waste” mode.
Keep the water moving by running the pump and filter for several hours a day. Yellow algae tend to thrive in stagnant water, so keep it circulating.
Step 2 – Testing and Shocking
Before you learn how to get rid of mustard algae in swimming pool for good, you’ll need to first test the water to ensure that the pH and alkalinity are balanced. Most people use strips or meters. The ideal pH level in a pool should be approximately 7.5 Algae thrives is anything much higher than that. The ideal ppm for the alkalinity should be between 80 and 140.
If the pH level is over 7.6, lower it by adding sodium bi-sulfate or muriatic acid. After treatment, wait at least an hour before testing again.
Once the pH level is stabilized, the alkalinity level should naturally follow.
Before the shock treatment, begin the shock treatment. Put all cleaning equipment and hoses at the shallow end of the pool. Wait until NIGHT time to actually do the shocking; the sun will reduce the effectiveness of the chlorine.
A product like calcium hypochlorite is usually recommended. Use approximately 3 pounds (1.36-kg) for every 10,000 gallons of water.
Whatever type of product you use, make sure you follow the manufacturer’s instructions clearly.
Eliminating the Algae and Preventing it from Coming Back
Now that you know how to get rid of yellow algae in pool, you need to know how to prevent it from coming back.
Hopefully, it will be gone when you test it again the next morning. Make sure the pool is still balanced. Take the brush and continue scrubbing the areas where the algae have been just in case any residue might be remaining behind.
The ideal type of brush depends on what kind of pool you own. For unpainted concrete surfaces, use a scrubber with stainless steel bristles. For vinyl, painted concrete, or fiberglass, use vinyl or nylon bristles.
Keep the chlorine running high and continue testing the pH and alkaline levels over the course of a few days. If there are no signs of the algae coming back, congratulations – you completely eliminated it. If it does, however, start the process over again.
You might want to go ahead and shock it again anyway at normal strength just to be sure. Don’t forget to clean out the filters.
Now that you know how to get rid of the algae, you might be wondering if it’s too much work. The process isn’t as difficult as it might seem as long as you follow instructions. Your pool is an investment, so you’ll want to preserve it for as long as possible and the steps necessary to ensure that it is sparkly clean.
Make sure it does not come back. Keep an eye on the pH and alkalinity levels regularly and don’t forget to run the pump regularly so that the water doesn’t become stagnant.