Green is for grass. Green isn’t a great color for your pool.
Blue is the best color for your swimming pool.
But, what if yours is turning green? Algae is the culprit, and with our hot weather and rainy days, let’s look at how to return your pool to sparkling blue.
If your pool water is green, and nothing is helping, we’ve got three different ways to help you get rid of it quickly.
First, let’s look at what algae is and how it’s formed.
What is Algae?
Algae are plants or plantlike organisms that can be microscopic or large such as giant kelp. Algae in your pool can be green, yellow (mustard) and black. You find it growing in water, and when that happens in your pool, you’ve got a problem.
Why did my pool get algae?
Water and algae go hand-in-hand. In order to keep it out of your pool, you need to treat your water regularly.
You’ll find that algae blooms happen in pools that don’t maintain proper sanitation and circulation. If water isn’t moving, algae grows.
You want to use your pump and filter to keep the water moving to avoid algae growth.
In addition, look under your ladder, on your pool steps, under the diving board, and in the corners and crevices for hiding algae.
Next let’s look at the three different kinds.
Green Pool Algae
This is the most common type of algae found it swimming pools, and it grows when there isn’t proper sanitation and filtration.
You might see green or blue algae floating in your water causing the pool to look green. Or, you see it clinging to the walls or on the bottom of the pool. You can easily brush it off.
This kind is easy to get rid of with sanitizer or algaecide.
Yellow/Mustard Pool Algae
Mustard algae grows on pool walls when they don’t see much sun. It’s very common, but harder to kill than green algae. To get rid of it, you have to super-shock your pool with a high dose of chlorine.
Black Pool Algae
Not very common, you really don’t want to see this in your pool because it’s very hard to get rid of. You’ll see dark spots on your swimming pool walls. Plus, black algae protect itself with strong roots that grow deep.
Even if you take care of your pool, you might see this kind. To kill it you need a lot of chlorine and a heavy-duty pool brush.
We’ve got three methods for getting rid of green algae in your swimming pool.
Method #1: Shock the Pool
Green algae comes in three stages: light, dark green and black green. The more algae in your pool, the darker the color.
If your water is light green, double shock your pool. One pound of shock can treat up to 10,000 gallons of water. For example, if you have a 10,000-gallon pool or less, you need to double shock it by adding two pounds of shock.
For pool water that is dark green, you want to triple shock it. so, if you have a 10,000-gallon pool or less, you need to add 3-pound bags of shock.
If your swimming pool is full of black/green water, you need to quadruple shock it. In this case, if you have a 10,000-gallon pool or less, you need to add 4-pound bags of shock.
Note: If you have a vinyl liner pool, dissolve each 1 lb. bag in its own bucket of water before putting it in the pool. This prevents your liner from being bleached by the shock. NEVER POUR SHOCK THROUGH THE SKIMMER IF YOU HAVE AN AUTOMATIC CHLORINATOR. And remember, always shock at night. Chlorine burns off 1 PPM (Part Per Million) every hour in direct sunlight causing the chlorine to drop below break-point oxidation required to kill algae.
Method #2: Floc the Pool
Floc (Flocculant) is a chemical that takes all the small particles in your pool like algae and settles them on the bottom.
After all the particles have settled, you can vacuum them off the bottom of your pool.
You’ll find this method time-consuming, but it gets rid of your algae quickly. Here’s how to do it:
How to Floc the Pool
- If you have a multi-port valve on your filter, shut off your pump and turn the valve to “Recirculate” or “Recycle.” This stops the water from flowing through your filter. It does spin the water around to help mix in the chemical.
- Add the recommended dosage of Flocculant to your pool. Floc comes in liquid and powder form. Make sure you check the directions for the right dosage for your size swimming pool.
- Circulate the water for about two hours to get the chemical fully mixed in, then shut off your pump and let it sit overnight. During this time, the chemical starts to bind the particles together and settle them to the bottom of the pool. In the morning, you should wake up to a nice healthy particle cloud at the bottom of your pool.
- Hook up your manual vacuum cleaner. Before you turn your filter on, make sure you have your multi-port valve set to “Waste.” Your filter will not be powerful enough to clear the water that fast, so cloudy (or green) water will just shoot back into your pool through the return lines. You don’t want this. Also, make sure you hook up your backwash hose to the backwash/waste port and direct the hose where you want your dirty water to go.
- Add your garden hose to the pool and turn it on while you vacuum. Since you are vacuuming to “waste” which will dump a lot of water out of your pool, it’s best to have your garden hose replacing the water with clean water as you vacuum out the dirty stuff.
- Slowly vacuum the bottom of the pool. You are sucking out thick, dirty water from your pool, and as you move the vacuum across the pool floor, it’s going to kick up debris. When it becomes too cloudy to see what you’re doing, shut off your pump and let it sit for a couple of hours to resettle. Then you can go back and continue vacuuming. You may have to do this several times depending on how much debris you need to vacuum.
- When you are done vacuuming the pool and everything looks good, double shockyour pool to make sure all the algae has either been removed or destroyed.
Method #3: Use Algaecide
You want to use algaecide as a preventative throughout the pool season to keep algae from growing in your swimming pool.
While there are some algaecides that do kill pool algae, it’s not the best method for killing it. It is, however, a great way to prevent it.
Method #1 is perhaps the easiest and least expensive way to kill algae. If you want to get rid of algae fast – like right before a party – Method #2 is good. Method #3 is recommended for the prevention of algae.
Need some help? Contact our service department – we are here to help!
Source material: Swim University