Pool Algae: Fight the Battle and Win the War!

Algae. The battles rage on in backyards across America. Our enemy? Algae – villainous, single-celled creatures. Not smart, but surprisingly well organized.

Fight the good fight against algae by joining our resistance movement; and restore order and blue water to your backyard pool.

This is guerrilla warfare. The enemy seems to materialize out of nowhere. Microscopic algae spores can enter your pool from so many different sources. Rain, wind, dirt, swimmer’s bathing suits, or even swimmer’s skin are some of the main points of entry for algae.

We can’t control the their point of entry, but we can flank them from all sides to restrict their movements and cut off their food supply lines. Preventing algae attacks requires a strong defense, focused on chemical warfare and hand-to-hand combat.

Time spent to prevent algae from ever growing in the first place is far better than time and frustration spent trying to clear up an algae bloom.

How to Prevent Pool Algae

algae-bomb - blow up your pool algaeRun your filter system at least 8 hours a day. 12-15 hours daily is even better. The longer you run your filter, the clearer your water will be, and the less likely you are to develop algae.

algae-bomb - blow up your pool algaeMaintain chemically balanced water. Get in the habit of testing your pool at least 2-3 times weekly and make the necessary adjustments. Algae grows slowly in properly balanced water.

pool-chemical-level-chartProper chemical ranges for chlorine or bromine pools. For more infor regarding testing and maintaining proper readings in your water, see Brett’s recent post “Pool Testing: Why, What & How”

algae-bomb - blow up your pool algaeShock your pool weekly. Shocking your pool helps to kill any small amounts of algae that might be resistant to your regular chemical warfare program. Follow label instructions.
algae-bomb - blow up your pool algaeBrush and vacuum. Regularly vacuuming and brushing the pool (weekly or more often if possible) will help to break up any algae particles that are perhaps not visible yet.
algae-bomb - blow up your pool algaeUse a phosphate remover. Phosphates are “algae food” and can be introduced to the water from plant debris, fill water, rain water, fertilizers, and some soaps and detergents.

Phosphate removers like PhosFree and SeaKlear Phosphate Remover starve the green enemy by removing phosphates from the water. Algae cannot grow in a pool that has proper sanitizer levels and no phosphates.

Types of Algae

If you have already developed algae, you need a plan of attack to get rid of it. First, determine what type of algae you are battling against. Green algae is by far the most common, but we have identified 3 main enemy factions.

Green Algae in Pools

Green algae is the largest group of insurgents. They can develop and spread very quickly (often overnight) and can be free-floating, suspended particles, large wall sheets or greenish spots, hiding in crevices. It has a slippery/slimy feel and can cause the pool water to become quite cloudy. Green algae is generally pretty easy to kill, but if left untreated for too long, it will become a widespread problem and require more effort.

Yellow/Mustard Pool Algae

Yellow (or mustard) algae appears as a powdery deposit on the pool, almost like sand.  It is not slimy like green algae and it does not cloud the pool water. Sometimes it is mistaken for copper or metal staining, but unlike metals, it brushes off easily.

Yellow algae is a more cowardly regiment of the algae army, usually found in the shady areas of the pool, or hiding behind underwater lights or under pool ladder treads. Once established however, it is chlorine resistant and can survive with 3-5 PPM of free chlorine present in the water.

Black Pool Algae

Black algae is an elite force and the most chemical resistant type of algae. It forms black/dark blue-green spots, usually under 1 centimeter in size. Their layered structure puts down roots in rough, etched or pitted surfaces (especially plaster or grout) and continue to grow back as long as those roots are present.

The first layer of black algae (the head) can be killed if the surface is disrupted, so that chlorine can enter the organism. The root however, can disconnect from the head in self-protection. Getting chlorine into the root cell of the organism, into their trenches, or a bomb into a bunker, is the only way to effectively put down the threat.

How to Kill Algae

algae-bomb - blow up your pool algaeBalance the water. The first step to treating algae is to adjust your pool water, especially your pH. An algae bloom can cause the pH to rise, so lower it to 7.2.

algae-bomb - blow up your pool algaeRun the filter. Make sure your filter system is running 24 hours a day until the algae clears. Clean and backwash the filter when the pressure gauge indicates.

If you have floating green algae, shock the pool, carefully following the directions on the label. To completely kill green algae, a level of 30 ppm of chlorine should be achieved. This typically is a triple-dose of shock, or 3lbs granular shock per 10,000 gallons of pool water.

24-48 hours later, or once the chlorine level has dropped below 5.0 ppm, add algaecide. Our Super Algaecide is an excellent chemical to add after shocking the pool. Copper can cause staining in plaster pools if over-used, so follow the label instructions, especially if you use well water or otherwise have a high metal content.

algae-bomb - blow up your pool algae Brush the pool. Walls and floors towards the main drain. Allow the pool to filter for a day or so after adding the algaecide. Using a flocculent clarifier may be a good choice if the pool is still very swampy, this will help speed up the settling of dead algae.

algae-bomb - blow up your pool algae Vacuum the pool. Be sure to thoroughly clean your filter after treating an algae bloom. If your filter traps algae particles that you do not remove, water will run through it and possibly re-contaminate the pool.

algae-bomb - blow up your pool algae Test & Balance. Make sure that your water is re-balanced after treating the algae. Chlorine, pH, Alkalinity, Calcium & Stabilizer levels.

If you have black or mustard algae, you can follow the same basic process above, but be sure to thoroughly scrub the algae before you shock to weaken it and help make the chlorine more effective.

As mentioned above, black algae has several layers, and the first protective layer must be removed so chlorine can kill the plant at the roots. Scraping off the heads with a pumice stone works well on black algae. After scrubbing, sprinkle granular chlorine over the algae spots or rub them with a chlorine tablet. Of course, this is not a great option for vinyl liner pools, as you may bleach the liner.

Yellow algae is very chlorine resistant, so we bring out the big guns. Chlorine enhancers like Yellow Out is added with chlorine shock to accelerate the killing power of chlorine to quickly eliminate algae. Yellow out requires that you raise your pH prior to treatment and run your filter for at least 24 hours after treatment, so if you decide to try this product be sure to follow the directions on the label, not what I’ve described above.

Yellow out can also be used to treat a bad green algae bloom. It is well known for clearing up algae within about 24 hours if you follow the directions properly.

Hopefully these battle strategies will help you get In The Swim again in no time! Do you have some tips for treating algae that I haven’t mentioned? Please leave us a comment and let us know. As always, if you have any questions about how to wage war on algae in your pool give us a call at 1-800-288-7946.

Jackie Wolski
InTheSwim Staff Blogger

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