Green to Clean
Transforming your pool is easier than you think

When life gets busy, pool maintenance can be the first to get overlooked. Maybe you went on vacation or got caught up in the day-to-day. Does one week really make a difference? these things happen all the time… but then you wake to every pool owner’s nightmare.

Your stomach sinks when you see a green swamp where your blue oasis once was. Panic sets in as your brain is flooded with all your upcoming pool events! Anxiously, you grab your phone to search, “How do I turn my pool blue ASAP?” (perhaps this is how we met?). Presented with a myriad of advice, almost all of which conflict with each other, and to top it all off, you must wade through endless ads promoting magic chemicals, potions, and products brought to you by the swimming pool industry.

As desperation sets in, you decide to bring a water sample to your nearest pool supply store with hopes they can help. They hand you a printout of your pool readings and list of chemicals that feels like a mile long, all necessary to turn your pool blue. Reluctantly, and a few hundred dollars later you’re back home, with a wagon full of chemicals, your handy dandy print-out, and no clue what to do next… Sound familiar?

Don’t worry – it happens to the best of us. Good news is transforming your pool from green to clean is easier than you think. In this article, we will guide you through the steps to remedy your green situation. Let’s jump in and get your pool sparkling – the easy way.

Let’s start with why your pool is green?

When pools are a cloudy green the culprit is almost always algae. But how did it get there ?

Algae enters the water by various means. Algae are microscopic plant-like organisms that are carried by wind and rain and are naturally present in the environment. Once in the water, they thrive and multiply rapidly if the conditions are right – such as warm temperatures and sunlight combined with a lack of sanitation and water balance.

When algae takes hold, they can turn your pool water green at a shockingly fast rate, taking about 4 hours to double in population. So – how do we destroy these microscopic trespassers?

How long can the process take?

Depending on the type and condition of the filter, it can take anywhere from 3 days to 2 weeks to completely clear up a pool. DE filters will work the fastest, sand filters the slowest and cartridge filters fall somewhere in the middle.

Fighting algae is a race against its rapid growth – you need to kill it faster than it grows – and in order to do so you need non stop filtration and chlorination. Any chemicals used to kill algae in the absence of nonstop filtration will be wasted.

Focus on the Filtration.

The first – and arguably the most important part of the Green to Clean process – is to make absolutely sure your filtration system is running 24/7. You should also be familiar with how to clean or backwash your system. For cartridge and DE systems, now is a great time to reach out to an Amenity Pool Services Pro for support on cartridge and DE cleaning.

Why it’s important to have a high quality test kit

One of the best investments you can make is a quality test kit. There are hundreds of cheap test kit options on the market but you need to get a test kit that is capable of testing pH, total alkalinity, calcium hardness, cyanuric acid, free chlorine and combined chlorine. The chlorine tests should utilize the DPD method. A very popular option is the Taylor 2005 series test kit.

Have you heard about cyanuric acid?

It is important to understand the relationship between cyanuric acid (aka chlorine stabilizer) and free chlorine level when dealing with a green pool.
A common analogy when approaching cyanuric acid is that it is like sunscreen for chlorine. Without a minimum amount of cyanuric acid, chlorine is quickly burned off by UV rays from the sun. (recommended min 30ppm) At the same time, cyanuric acid levels higher than 100 ppm “overprotect” the chlorine, causing it to be less effective.

Depending on the intensity of the sun in your geographical location; levels around 50 ppm work well in Florida and most of the Southeast, 60 – 80 ppm work well in sunny areas like Arizona or South Texas, and 30 ppm work well in seasonal markets like the Northeast.

If your cyanuric acid level is over 100 ppm, it is recommended to drain a portion of your pool water and refill with fresh water to bring your levels down (30 to 50 ppm).
If your cyanuric acid level is under 30 ppm reach out to your Amenity Pool Services Pros for assistance.

Adjusting the pH level

Now that we know about cyanuric acid, let’s look at pH. While it is ideal for pH to be within 7.2 and 7.4, you may have heard that “chlorine is more effective at a lower pH. This is true for unstabilized pools (no cyanuric acid) and partially true for pools with cyanuric acid. Most algae destroying chemicals, like chlorine, produce bi-products that raise your pH. Chemicals like pH down (“sodium bisulfate”) or liquid muriatic acid can be used as a proactive step to lower your pH.

Now it is time to address the algae

It is not possible to kill algae through conventional means. Simply adding a few tabs to the chlorinator or turning up the salt generator is not going to do the job!

The amount of chlorine you need for this step can be surprising, and I understand you may feel uncomfortable doing so. We need to increase the free chlorine to 30 ppm repeatedly until all of the algae is gone. You can use calcium hypochlorite (a granular powder) or sodium hypochlorite (liquid chlorine) for algae destruction.

To get to 30 ppm you would need:
3 gallons of liquid chlorine per 10,000 gallons OR 4 lbs of calcium hypochlorite per 10,000 gallons
So, if you have a 25,000 gallon pool – you would need 9 gallons of liquid chlorine OR 10 pounds of calcium hypochlorite

Preferably in the early evening to avoid any interference from the sun, add all of your calculated chlorine into the pool water (not the skimmers). Make sure you are running the filter 24/7 during this time.

The next morning, check your filter. In the case of sand or DE filters, backwash when the pressure is 15% above your clean pressure. Cartridge filters should have the cartridge cleaned again (this time you can just rinse it off with water). Now is also a great time to brush the pool, knock off any algae on the walls and floor, giving the chlorine a better chance to kill it off.

Check you chlorine level

Are you below 5.0 ppm or above 5.0 ppm ? If you are below 5.0 ppm, the chlorine you added the night before has been completely consumed by the algae. This means that the chlorine is working and is doing its job – but – we will need another dose and should bring the level back to 30 ppm once again.

If you are above 5.0 ppm, wait at least six hours to check the free chlorine level again. Do not add more chlorine to the water until you drop below 5.0 ppm. The trick to this is to never let the chlorine get to zero but also to allow it to be consumed by the process of killing the algae.

Repeat this process of backwashing, brushing the floor, and raising the chlorine level to 30 ppm until the algae is completely gone. Evaluate whether another dose is needed each time the free chlorine level drops right below 5.0 ppm.

You will know that you got the algae completely out of the water once the combined chlorine level drops below 1.0 ppm, the water is completely clear, you stop losing free chlorine overnight, and there is no green slime in the corners of the pool.

How do you keep this from happening again?

The answer is simple – run your filter more often and keep your free chlorine level at least at a 3.0 ppm at all times (5.0 ppm is preferable). You may find that you need to run the filter more in the summer months. These two factors are the most important part of pool maintenance.
Reach out to an Amenity Pool Services Pro for more information about Algae prevention and treatment plans.