Mustard Algae Treatment: How to Kill and Prevent Mustard Algae in a Pool

Isn't it just the worst feeling when you glance into your backyard, hoping to see your pool shimmering under the Australian sun, only to find it looking more like a swamp than a retreat?

Mustard algae can turn that dream oasis into a nightmare faster than you can say "cannonball". If you've ever stood poolside, scratching your head and wondering how on earth you'll tackle this pesky problem, you're not alone.

The Mustard Algae Dilemma

Has your pool ever looked a bit off, like it’s sporting a yellowish tint that refuses to budge? That sneaky visitor is mustard algae, clinging to walls and surfaces with a stubborn persistence that defies regular cleaning methods. Despite your best efforts with the brush and standard chlorine, it has a knack for returning. 

For us Aussies, this algae outbreak can be particularly frustrating. Mustard algae thrive in warm climates and can also hitch a ride into your pool on swimsuits or equipment that carries lingering spores.

Unsuspecting wind and rain can even introduce it from nearby water sources. Once settled, its rapid ability to multiply in the right conditions makes it a formidable opponent, especially if your pool’s chlorine levels aren’t consistently maintained.

Where Does Mustard Algae Come From?

Understanding how mustard algae enters your pool can help you prevent future outbreaks.

Unlike some algae that form spontaneously in poor water conditions, mustard algae typically enters your pool through specific vectors:

• Contaminated swimwear or pool equipment that's been used in natural water bodies

• Wind-borne spores, especially after heavy rain or storms

• Pool toys or floats stored in damp, dark places

• Contaminated fill water, particularly from bore sources

Mustard algae is particularly resilient because it can lie dormant and survive in dry conditions, including on pool covers, toys, and even swimwear.

This means it can reintroduce itself to your pool even after successful treatment if these items aren't properly disinfected.

Is Mustard Algae Harmful?

While mustard algae isn't typically as dangerous as some other pool contaminants, it's not something you want to swim with. Mustard algae can:

• Harbour bacteria that may cause minor skin or eye irritations

• Create slippery surfaces that pose safety hazards

• Potentially cause respiratory irritation in sensitive individuals

• Compromise your pool's sanitisation system by consuming chlorine

Though rarely causing serious health issues, a mustard algae-infested pool is not properly sanitised, which means other harmful microorganisms could be present.

It's best to keep everyone out of the pool until the problem is resolved and chemical levels have returned to normal ranges.

How to Identify Mustard Algae in Your Pool

Not sure if that yellowish film is actually mustard algae? Unlike its green cousin, mustard algae (also known as yellow algae) can be more challenging to identify because it often resembles sand or dirt on your pool surfaces.

Here's a simple test to confirm if you're dealing with mustard algae:

1. Brush the affected area firmly with your pool brush

2. If the substance clouds briefly but then settles back onto surfaces within hours, it's likely mustard algae

3. Mustard algae also tends to return quickly after chlorine treatments that would normally eliminate standard algae

Another telltale sign is location. Mustard algae typically appears in shaded areas of your pool and has a distinctive yellowish-brown or mustard colour that can sometimes appear powdery.

Practical Steps to Win the Mustard Algae Battle

We’ve helped folks restore their slice of paradise, and we’re here to do the same for you. Here’s how:

1. Deep Clean Your Pool

Start by vacuuming your pool thoroughly and scrub away any algae on surfaces. It’s tedious work but could be the difference between success and another algae outbreak.

2. Test and Adjust Chemicals

Ensure your pH levels are in the ideal range (around 7.4 to 7.6). Mustard algae are surprisingly resilient and thrive when things are off-balance.

3. Shock Treatment

You’ll need to shock your pool with high doses of chlorine. Think of it as calling in reinforcements. For effective mustard algae elimination, use calcium hypochlorite shock at a rate of 1kg per 50,000 litres of pool water—roughly double the normal shock treatment dosage.

The key to success is achieving a free chlorine level of 10-12 ppm during the treatment process. This intensive treatment usually takes about 24-48 hours for best results. For particularly stubborn infestations, you might need to repeat the shock treatment after 48 hours.

4. Algaecide Application

Add a quality pool algaecide specifically formulated for mustard algae. At Algaefree Australia, our Pool Blocks All Seasons Algaecide is particularly effective against mustard algae when used at a dosage of 1 litre per 50,000 litres of pool water.

For best results:

• Add the algaecide during evening hours to prevent UV degradation

• Distribute it evenly around the pool's perimeter

• Keep your filter running for at least 8 hours after application

5. Clean and Repeat

Run your pool system continuously for at least 24 hours and re-check that everything is balanced. Clean your filter afterwards to remove any lingering algae spores.

Pool Blocks All Seasons Algaecide

Keeping Mustard Algae at Bay

Prevention is truly the best cure, especially when it comes to mustard algae. Here are some proactive steps to help you keep your pool pristine:

Regular Maintenance

Establish a routine for pool cleaning and maintenance. Consistent vacuuming, scrubbing, and chemical balancing form the first defence line against algae formation.

Balanced Water Chemistry

Frequently check your pool’s water chemistry. Maintaining the proper levels of chlorine, pH, and alkalinity significantly reduces the chance for mustard algae to thrive.

Filter Care

Ensure your pool’s filtration system is working optimally. Clean the filter regularly to remove any caught particles or spores that could lead to algae problems.

Circulation is Key

Ensure your pool water is circulating effectively. Proper circulation helps prevent stagnant areas where algae are most likely to develop.

Cover Up

When not in use, cover your pool to keep debris and sunlight (which algae need to grow) out. It’s a simple yet effective step to prevent algae formation.

When Mustard Algae Keeps Coming Back

If you've followed all the steps but still find yourself battling recurring mustard algae, don't despair. Here are some common reasons treatments fail and how to address them:

Inadequate Cleaning of Pool Accessories

Thoroughly disinfect all pool equipment, toys, and swimwear in a chlorine solution (1 cup of liquid chlorine per 10 litres of water). For items that can't be soaked, spray with a chlorine solution and allow to dry in direct sunlight.

Insufficient Filtration Time

Run your filter 24 hours a day during treatment and for at least 72 hours after the pool appears clear. Mustard algae particles are extremely fine and require extended filtration to remove completely.

Compromised Filter Media

If you've had recurring algae problems, consider replacing your sand or DE filter media, as algae spores can become embedded and reintroduce contamination.

Sheltered Problem Areas

Pay special attention to areas with poor circulation or regular shade. Consider installing additional return jets or water features to improve circulation in problem zones.

Remember, persistence is key when dealing with stubborn mustard algae. With the right approach and quality products, your pool will be back to its sparkling best.

Take the Plunge with Confidence

So, the next time you see that yellow invader creeping in, remember that you’re not alone and you’re most certainly not defeated. Muster up your courage, follow these trusted techniques, and you’ll have that sparkling pool ready for the barbie in no time.

Ready to get started? Dive into our range of Algae & Black spot Removal products at Algaefree Australia or give us a shout for more personal guidance. We'd love to hear from you; think of us as your poolside ally in this battle against the algae! Stay cool, Australia, and happy swimming!