ALGAE: Algae is a major concern for pool owners. Algae is a one-celled plant that can grow in your pool if conditions are favorable.

For more specific information on algae, select from the following topics:

• WHY DOES ALGAE GROW
• PREVENTION OF ALGAE
• TYPES OF ALGAE
• ALGAECIDE
• TYPES OF ALGAECIDES
• BEGINNING STAGES OF ALGAE
• PINK SLIME IS NOT ALGAE
• HOW TO KILL GREEN ALGAE
• HOW TO KILL MUSTARD ALGAE
• HOW TO KILL BLACK ALGAE
• ADDITIONAL INFORMATION ON ALGAE TREATMENTS

WHY DOES ALGAE GROW: Algae is a major concern for pool owners. Algae is a one-celled plant that can grow in your pool if conditions are favorable. The most common myth concerning algae growth in pools is that it is ONLY a result of low chlorine (or its alternative). Although this is definitely a major cause of algae, it is not the single contributing factor.

Despite water treatment facilities, actual traces of algae may very well be present in the tap water that is used to fill your pool. Therefore, it is always a good idea to add an algaecide and to shock your pool after it has been filled or refilled. Yet another contributing factor toward algae growth are millions of microscopic algae spores that are carried by wind, eventually falling into your pool, where they will grow into outbreaks of algae if conditions are favorable.

A few of these favorable conditions are environmental. Algae, like all plants, need light and food in order to survive and grow. Temperature, humidity, sunlight, and nutrients (food) foster algae growth. Temperature, humidity and sunlight are self-explanatory. Nutrients consist of lawn fertilizers and other industrial products that are carried by wind and blown into the pool. Nutrients also consist of certain minerals that are already present in water. Since water chemistry relies on some of these certain minerals to be present, they cannot simply be removed from the water.

Here is a possible sequence of events: Algae spores will blow into your pool, where they are supported by temperature, humidity and sunlight. The algae spores then consume various nutrients. From temperature, humidity and sunlight, as well as from nutrients, the once unnoticeable algae spores have now grown into actual algae.

In addition to these environmental factors, other factors, such as limited water circulation, poor filtration, a neglect of routine pool maintenance, heavy bather loads, a neglect of overall water chemistry, neglect of shocking, and of course, insufficient levels of chlorine (or its alternative), also make conditions favorable for algae growth.

Algae is not harmful to swimmers. It just causes the appearance and integrity of your pool to suffer and occupies time to correct. If you do get algae, you are not alone; it has been seen in pools of some of the foremost authorities on pool care and maintenance. Rest assured, any algae can be killed, but not without a few days of continued effort and time. Therefore, it is best to begin with a discussion on the necessary steps to prevent algae growth. An ounce of prevention is worth a hundred pounds of cure.

PREVENTION OF ALGAE: You cannot control temperature, humidity, and sunlight, and you can administer little control over nutrients in the water, especially since your pool needs certain minerals present in order to achieve water chemistry. But, you can control non-environmental factors, such as maintaining adequate water circulation, proper filtration, a routine maintenance schedule, an overall attention to water chemistry, sufficient chlorine (or its alternative) levels, and routine shocking, while always compensating for climate and bather load. Attention to these factors is your best defense in preventing algae. Also, if you want, you can purchase an Algistat from your local pool professionals and add it periodically to your pool. An Algistat will assist the other chemicals to help prevent algae growth, but it is useless if algae is present.

But, here is some bad news: even with proper water chemistry, sufficient chlorine (or its alternative) levels, regular shocking, and a demonstration of superior operational and maintenance procedures, the presence of some algae is still possible. There are just too many contributing factors for the presence of algae. Since algae growth is a slight possibility for trained pool owners and a real probability for other pool owners, poolmanual.com will provide treatments to kill algae. An initial piece of advice is that algae is far easier to prevent than it is to kill. But, should algae grow, another piece of advice is not to panic-algae is beatable.

TYPES OF ALGAE: Although there are over 20,000 known varieties of algae, fortunately for pool owners, there are only three types commonly found in pools-green algae, mustard algae, and black algae.

Green algae is the most common variety of algae found in pools. Mustard algae and Black algae occur less frequently, but if either does occur, their removal is much more difficult. Unfortunately there are no miracle cures that will get rid of algae. Although some manufacturers of algaecides make this claim, let it be understood that there is NO chemical (algaecide) that you can add to the pool water, walk away, and expect the algae to disappear overnight. Each type (color) of algae requires its own treatment.

ALGAECIDE: An "as-needed" chemical. If algae does occur, Algaecides are used to help kill algae. The majority of algaecides are liquid, but some types do come in granular form. Once you determine the type of algae (green algae, mustard algae, or black algae), you can purchase the appropriate algaecide and begin the proper treatment. Then read the instructions on the label to determine the amount to add, how it should be added (most manufacturers of algaecides recommend pouring it straight from the bottle), and other precautions. An algaecide alone will not kill algae. You will need to add heavy doses of shock (at least 2 LBS per 10,000 gallons of water) and engage in a demanding maintenance schedule, primarily brushing.

TYPES OF ALGAECIDES: There are four general categories for algaecides.

• [POLYMERIC ALGAECIDES]
• [QUATERNARY ALGAECIDES]
• [METALLIC ALGAECIDES]
• [CHLORINE-ENHANCERS]

POLYMERIC ALGAECIDES: (Polymers) contain a positive electrical charge, which is attracted to the negative electrical charge of algae. This is an excerpt from a Chemistry 101 lecture, but do not worry about the chemistry behind polymers. Rather, just understand that polymers will attach to algae in order to kill it. A drawback is that polymers also attach to dirt and debris found in pools, thus diluting the strength. This can be combated by brushing the pool, stirring up the dirt and debris, as well as the algae, allowing the chlorine (or its alternative) to kill it or to send it to the filter for removal from the pool. It can also be combated by adding slightly more than the recommended amount of the polymeric algaecide in order to compensate for any dirt or debris that still may be present. Polymers are most effective for killing green algae, as they attach and invade the weak outer shell of algae, then penetrate inside, smothering the algae's ability to live and grow. Polymers are fairly ineffective at killing mustard algae or black algae.

QUATERNARY ALGAECIDES: (Quats) are like polymers in that they contain a positive electrical charge, which is attracted to the negative electrical charge of algae. But, this positive electrical charge is really just a slight version of that of the polymers, rendering quats virtually ineffective and out of date. Quats can be effective at preventing algae growth, but they do cause the water to foam. Therefore, to help prevent algae, quats have been replaced by the algistats, which do not foam. Today, you will have difficulty finding many pool professionals that sell quats. If your pool professionals sell quats, poolmanual.com recommends never purchasing or using them.

METALLIC ALGAECIDES: Contain copper. Although copper is superior at killing all varieties of algae, it is a mineral that is not desired in your pool, as it is corrosive. The presence of copper will dissolve metallic materials in your pool (walls, floor, hand rails, ladders, light fixtures, and equipment), which will discolor your pool water and may stain your pool walls or floor; or worse, may destroy your equipment. If a Metallic Algaecide is used, you will also need to add a Metal Sequestering Agent to the pool water within one week of applying the Metallic Algaecide in order to rid the pool water of the undesired copper. Metallic Algaecides are most effective for killing harsh mustard algae or black algae.

CHLORINE-ENHANCERS: Do not kill algae by themselves. As the name implies, Chlorine-enhancers team with chlorine to kill the algae. Algae will mistake this special chlorine-mixture for food, take it in for consumption, and die. Although effective, the drawback of chlorine-enhancers is that they require a multiple step process of chemical adjustments. Since killing algae is already labor intensive and time-consuming, use of chlorine enhancers is often bypassed. If used, chlorine enhancers are most effective for killing harsh mustard algae or black algae.

These four categories of algaecides all have their pros and cons. Poolmanual.com recommends Polymeric Algaecides to kill Green algae, either Metallic Algaecides or chlorine-enhancers to kill Mustard algae, and Metallic Algaecides to kill Black algae. All pool professionals carry a full line of algaecides. Listen to their advice on the best algaecide for your particular type (color) of algae.

BEGINNING STAGES OF ALGAE: In its initial stages, algae will feel like a (clear) slime, causing the pool walls, floor, and any steps to be slippery. At this stage, shocking and brushing the pool probably will remove the embryonic algae; you may want to add some algaecide just to make sure-it is ALWAYS better to be safe than sorry. If algae is not detected and treated in this initial stage, color will begin to take form. Typically, algae will start to grow in the corners of the shallow end of the pool, and near the steps, primarily because circulation is not as thorough in these areas. Another reason that algae initially grows in the shallow end of the pool is that water is cooler in deeper waters; sunlight (which fosters algae growth) is less able to penetrate the deeper waters. Although algae typically grows first in the shallow end of the pool, if not treated immediately, it very well could infest the entire pool within hours. Therefore, if preventative measures did not work, treatment must begin immediately.

NOTE: Green algae and Mustard algae will typically start to grow in the shallow end corners. Black algae, which will appear as black specs-resembling dirt-in its initial stage, will start to grow in any area of the pool, regardless of water depth.

PINK SLIME IS NOT ALGAE: If a pink slime is witnessed, this is NOT algae, and it can be treated by brushing the pink slime to loosen it from the pool walls or floor and then by shocking the pool with a high dosage: 2 LBS per 10,000 gallons of water. The superchlorinated water and filter will kill this unsightly pink slime. Make sure to clean your filter to eliminate any remnants of the pink slime.

If it is a clear slime, this is algae in an initial and embryonic stage-begin your treatment immediately. Often, shocking and brushing the pool are all that is ever needed to kill algae in this early stage.

HOW TO KILL GREEN ALGAE: There are many treatment procedures offered for Green Algae. The following is just one of many treatment procedures available:

Day # 1:

• Brush the algae.
• Adjust the pH to close to 7.2, the low end of the ideal range.
• Add the required amount of a Polymeric Algaecide.
• Shock the pool that evening, using 2 LBS per 10,000 gallons of water.

Day # 2:

• That morning, brush any algae that may remain on the pool walls, corners, floor, or steps.
• After brushing, allow the water to settle, and then vacuum the pool.
• Immediately after vacuuming the pool, clean the filter in order to maintain proper and effective circulation and filtration:
  • For Sand filters or DE filters, backwash the filter.
  • For Cartridge filter, clean the filter elements with a garden hose and a pressurized nozzle.
• That evening, brush the entire pool to make sure all algae is loose and floating where it will be killed by the algaecide and the superchlorinated water and then sent to the filter for removal.

Day # 3 and beyond:

• Assuming that the algae is gone, monitor water chemistry and the chlorine (or its alternative) level, shock regularly, keep the equipment operational for a sufficient amount of time, and engage in a routine maintenance schedule.

NOTE: Test and adjust the chlorine (or its alternative) level daily throughout the treatment process. If the algae is still present after 2-3 days, add more algaecide and shock, and brush the pool more often.

HOW TO KILL MUSTARD ALGAE: There are many treatment procedures offered for Mustard Algae. The following is just one of many treatment procedures available:

Day # 1:

• Brush the algae
• Put all your maintenance equipment, water toys, bathing suits, and anything else that has recently been in the pool into the shallow end of the pool.
  • Mustard algae can live outside the pool. So, if you kill algae in the pool, but some mustard algae has attached to your maintenance equipment, water toys, bathing suits, or whatever, then mustard algae may reappear once these items re-enter the pool water. Therefore, put all these items in the shallow end of the pool prior to the treatment.
  • Make sure the telepole, brush, and complete vacuum assembly are in the shallow end of the pool and accessible, so that they can be picked up and used throughout the treatment process.
• Immediately after putting all maintenance equipment, water toys, bathing suites, etc into the shallow end of the pool, add . Read the instructions on the label to determine the required amount, and then add more than is specified.
  • The reason that you are adding more than the specified amount is that on day #3, you will fill the pool water level to the very top of the pool. You do not want to vacuum the mustard algae to your filter-it could take up residence there, and come back to your pool; again, mustard algae can live outside the pool water. Therefore, you will vacuum it to a waste-line (which is either plumbed into your system or manually set up). When you vacuum to the waste-line, you will lose this water from your pool. By filling your pool to the highest point, you can compensate for the water you will lose.
  • You have to compensate for the additional gallons of water that you will be adding to your pool. Therefore, add more than the specified amount, given the gallons of your pool.
• Wait at least five hours after adding the Metallic algaecide, and that evening, shock the pool, using 2 LBS per 10,000 gallons of water. o Again, remember that on day #3 you will fill the pool to its highest capacity in order to vacuum the mustard algae to the waste-line (bypassing the filter). o Since you will add this extra gallonage of water, also add 1LB of additional shock, to compensate for the additional gallons

Day # 2:

• Twice during this day, remove the telepole and brush from the shallow end of the pool and brush the entire pool. Put the telepole and brush back into the shallow end each time when finished.

Day # 3:

• Fill the pool to its highest point.
  • The standard operating water level should be halfway up the skimmer. If mustard algae is present, the water level must be filled to the very top of the pool. This will allow you to bypass the filter and vacuum the mustard algae to a waste-line. Again. the reason the filter is bypassed and the mustard algae is sent directly to the waste-line is that algae could live on the inside walls of the filter, get picked up by water during circulation, and re-enter and re-infest the pool.
  • Some pools do not have a capability to be vacuumed straight to a waste-line. If this is the case with you, do not fill the pool up to highest point and do not add extra Metallic Algaecide or shock. Rather, maintain your normal operating water level, add the required amount of the Metallic Algaecide and the required amount of shock-2 LBS per 10,000 gallons of water. Vacuum using your filter. You will need to stop often during the vacuum and clean the filter to make sure the Mustard algae is fully removed. Also, after the vacuum is complete, you will want to thoroughly clean the filter again.
    • For sand filters or DE filters, backwash the filter.
    • For cartridge filters, clean the filter elements with a garden hose and a pressurized nozzle.
• Immediately after filling the water level to its highest point (if applicable), remove the telepole and the entire vacuum assembly from the shallow end of the pool and vacuum everything out to the waste-line (or the filter if this is your only option). Regardless of how the pool is vacuumed, once finished, put the telepole and the complete vacuum assembly back in the shallow end of the pool. Also, use your garden hose to refill the pool to the standard operating water level (half way up the skimmer).
• That evening, brush the pool once more.

Day # 4 and # 5:

• At least once each day, remove the telepole and brush from the shallow end of the pool and brush the entire pool. Once finished, put the telepole and the brush back in the shallow end of the pool.

Day # 6:

• Remove all maintenance equipment, water toys, bathing suits, and anything else that was placed in the pool. Only remove these items if the Mustard algae appears to be gone.
• Brush the entire pool.
• Add a Metal Sequestering Agent in order to rid the water of any copper that may remain from the Metallic Algaecide.

Day # 7:

• Brush the entire pool.

Day # 8:

• Regardless of normal shock schedule, shock the pool, using 1 LB per 10,000 gallons of water.

Day # 9 and beyond:

• Assuming that the algae is gone, monitor water chemistry and chlorine (or its alternative) levels, shock regularly, keep the equipment operational for a sufficient amount of time, and engage in a routine maintenance schedule.

NOTE: The removal of Mustard algae is very labor-intensive and time-consuming; do you see why we stress preventative maintenance? Test and adjust the chlorine (or its alternative) level daily throughout the treatment process. If the algae is still present after day 7-8, add more algaecide and shock, and brush the pool more often.

HOW TO KILL BLACK ALGAE: There are many treatment procedures offered for Black Algae. The following is just one of many treatment procedures available:

Day # 1:

• Brush the algae…It will be difficult because black algae protects itself with a very rigid outer shell. Of the three varieties of algae, black algae has the most rigid outer shell.
  • If your pool is concrete, gunite, shotcrete, or fiberglass, use a stainless steel wire-bristle brush. Even though wire-bristles are more effective than your standard nylon-bristle brush, it will still be fairly labor intensive to remove this outer shell of black algae.
  • If you have a vinyl liner pool (or any type of an aboveground pool), use your standard nylon-bristle brush. Wire-bristles are too abrasive and may tear the liner. To compensate, add a stronger dose of shock, using 2 ˝ LBS per 10,000 gallons of water; make sure you dilute the shock-you do not want to tear the liner (with the wire brush), but you also do not want to bleach your liner (with the excess shock).
  • Note: Black algae does not discriminate where it will start - shallow end, deep end, corners, steps, pool walls, or the floor. Regardless of where it starts, brush these areas vigorously. Black algae appears first as little specs, resembling dirt. Although they start small with a slow growth rate initially, if not treated immediately, these specs will flourish into a massive outbreak of black algae.
• Throughout the day, brush the pool, and later that evening, after you have already brushed the pool once or twice, go ahead and brush it again.
• That evening, shock the pool, using 2LBS per 10,000 gallons of water (or 2 ˝ LBS per 10,000 gallons of water for a vinyl-liner pool).

Day # 2:

• Brush the entire pool at least twice throughout the day.
• After brushing the second time, add a Metallic Algaecide. Usually, pool professionals will offer a specific Metallic Algaecide that is specially formulated for Black algae.

Day # 3, # 4, and #5:

• Brush the entire pool.

Day # 6:

• Brush the entire pool.
• That evening shock the pool, using 1 LB per 10,000 gallons of water.

Day # 7 and # 8:

• Brush the entire pool.

Day # 9:

• Brush the entire pool.
• Add a Metal Sequestering Agent in order to rid the water of any copper that may remain from the Metallic Algaecide.

Day # 10 and beyond:

• Assuming that the algae is gone, monitor water chemistry and chlorine (or its alternative) levels, shock regularly, keep the equipment operating for a sufficient amount of time, and engage in a routine maintenance schedule.

NOTE: The removal of Black algae is labor-intensive and time-consuming; do you see why we stress preventative maintenance? Test and adjust the chlorine (or its alternative) level daily throughout the treatment process. If the algae is still present after day 8-9, add more algaecide and shock, and brush the pool more often.

ADDITIONAL INFORMATION ON ALGAE TREATMENTS: Even if you just shocked the pool the day before you noticed the clear slime, or actual algae itself, shock the pool again, using twice the amount of the normal recommended application. Do not allow swimming until the algae is gone. Any bather load and the possible introduction of swimmer wastes (such as perspiration, urine, saliva, or body oils) will tie up the chlorine (or its alternative) and the shock, taking them away from their intended job of killing algae. Although the algaecide is credited for killing the algae, it is virtually ineffective without chlorine (or its alternative), shock, brushing, continual water circulation, and proper filtration.

Regardless if you use our treatment procedures or those of your local pool professionals, just make sure that you do treat the algae. Too many pool owners hold off any treatment until they are absolutely, without-a-doubt, 100% sure it is algae. By this time, there very well may have been an algae bloom, infesting almost the entire pool. If you think that algae may be forming, immediately brush the entire pool and add shock, regardless of when you last shocked. Many times, brushing and shocking are all that is ever needed to prevent algae, and nip the problem in the bud.

If you are not sure whether or not an apparent growth is algae, here is a simple test: Play doctor and take a sample of the apparent growth from the pool. Place the sample in a clear jar filled with pool water. Then, add a teaspoon of diluted chlorine-based shock (this must be Calcium Hypochlorite or Lithium Hypochlorite, as both contain some chlorine. Potassium Peroxymonosulfate, which is a non-chlorine shock, will not work). Cap the jar and shake the sample in your hand. Set the sample down and come back within 1 hour. If the water has a green tint, you have a copper stain, and not Green algae. If the water has a brownish-red tint, you have an iron stain, and not Mustard algae. If the water has a brownish-black tint, you have a manganese stain, and not Black algae. If, however, the water turns clear, then you have algae, and you had better evaluate the color of the algae in your pool and begin treatment immediately.

Again, please remember that the best treatment for algae is its prevention. It is better to have to do minimal amounts of work periodically than it is to have to do labor-intensive work everyday, and at times, numerous times throughout the day. This simple daily work will also result in not having to give up your pool for 2-10 days, depending on the type and severity of algae.