Treating Your Swimming Pool Water:

Surface Staining

THE PROBLEM:
Dissolved metals and minerals are present in every swimming pool. These dissolved solids find their way into pool water in a number of ways: Fill water from wells or from city water lines can deposit dissolved minerals into the pool. Galvanized pipes and bronze or copper fittings in pool pumps and heaters are sources of iron, copper, and manganese. Foreign objects, from bobbie pins to pine needles, leave behind trace metals and minerals. Evaporation removes water from the pool, but leaves minerals behind, gradually raising the pool water's total dissolved solids level. Over time, these dissolved solids will precipitate, or "fall out" of the pool water, and settle into the surface of the pool. The resulting rust orange, brown, grey, and light blue-green stains are unsightly, and detract from the beauty of your swimming pool.

THE OPTIONS:
Among the options available to the homeowner are the following:

1. Periodically draining and acid washing the pool surface.
2. Mechanically removing minerals before they have a chance to deposit on the plaster. The type of filter required to remove minerals and heavy metals is called a nanofilter. It will clean the water to "bottled water purity" without having to drain water from the pool. Once the pool water has been cleaned with the filter, a chelating agent can be used to maintain the water in a "soft" condition.
3. Chemical treatments, which remove minerals before they have a chance to settle on the pool surface on the plaster. These chemicals are called chelating agents. Their name comes from the Latin word for "lobster claw." Chelating agents "pinch" dissolved metals and minerals, holding them until they can be strained out of the pool water by the filtration system. Chelating agents are also known as sequestering agents.

THE BENEFITS AND THE DRAWBACKS:

Draining and acid washing the pool will eliminate many stains, but it also accelerates pool plaster disintegration. Done by untrained or incompetent technicians, acid washing can lead to irreparable damage, from etching or pitting of the pool plaster to cracking of the pool shell.

The cost and quality of acid washing vary tremendously. Houston area pool companies typically charge between $125 and $600 for an acid wash! Since there is little regulation of the pool repair industry, you can't always be certain of the competence of the crew performing the acid wash -- the less expensive companies may actually provide the highest quality service! Whatever the cost, you must pay the expense of draining and refilling the pool, which typically runs in the $100 range.

Acid washing removes stains by dissolving a thin layer of pool plaster. The sort-term result is whiter, cleaner plaster, but the long term effects -- rougher, more stain-susceptible plaster

Nanofiltration costs $80 per day. Most pools require two or three days of nanofiltration. The nanofilter removes 300 to 400 parts per million of dissolved solids per day, greatly reducing the possibility that metals or minerals will "fall out" of the water.

There are a variety of chealting agents on the market. Thunderbird Pool Service offers YR-17, a very effective stain prevention treatment. Developed by a team of chemists and pool professionals in southern California, one gallon of YR-17 should be added to the pool every 4 months, all year 'round.

While YR-17 will not remove existing stains, it is an outstanding means of preventing new stains from forming.

COSTS:

Whatever stain prevention treatment you choose, there are costs involved. For example:

One acid was

1. $125 to $600 (with accompanying plaster disintegration) + $100 water refill costs = $225 to $700
2. 1 year of nanofiltration
3. About 4 days per year, @ $100 per day = $400
4. 1 year of YR-17
5. 3 gallons @ $35 per gallon = $105

CONCLUSION:
Regular maintenance is the best prevention against staining. Regular use of a chelating agent will prevent stains; preserve the appearance of your pool, and save the headaches and risks associated with nonfiltration and acid washing.

Some surface discolorations are not stains at all, but result from flaws in the pool plaster. For information on calcium chloride spotting, crazing, spalling, and other flaws please see our plaster problems page.

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Total Dissolved Solids

(Hard Water)

One of the measurements that can be taken on swimming pool water is the Total Dissolved Solids level, or TDS. TDS is a measurement of virtually everything dissolved in the water that is not H2O. This includes such components as salts, minerals (like calcium and magnesium), sulfates, silicates, organic and inorganic materials, tanning lotions and oils, sweat, saliva, urine, soap, deodorant, hair spray, colognes and perfumes, plant pollens, pet wastes, spilled food and soft drinks, dirt, lawn and garden fertilizers, etc. Wow! There is quite a lot of dissolved material in that water that is still clear to the human eye!

As water evaporates from the pool, the TDS increases because the sun only removes distilled (pure) water and leaves all of the dissolved solids behind (like when you leave a glass of water outside to evaporate... the white crust left behind was "dissolved solids"). The "fresh" water you then use to replace the evaporated pure water also contains its share of dissolved solids. Normal evaporation rates are usually up to 1/4" per day in the winter and 112" per day in the summer. Therefore the water in the pool is continually getting "harder", or higher in dissolved solid content.

High TDS can be a problem because they interfere with pH, hamper chlorine's ability to affect bacteria and algae, create hazy water, contribute to the corrosion of metal piping systems, and promote scale deposition on the plaster and tile.

In swimming pool applications, TDS is normally measured by means of a meter that passes electrical current through the water. Since most anything that is not pure water conducts electricity, and since pure distilled water does not, the amount of electricity that passes through can be read as a level of TDS.

Tap water TDS can range from 300 to 700 parts per million TDS. The average in swimming pools is usually 1000 to 2000 ppm. The National Spa and Pool Institute (NSPD recommends an upper limit of 3000 ppm).

TDS can be lowered through full or partial draining and refilling, through the use of chelating agents, or through special nanofiltration. If you wish to know the TDS level in your pool water, or if you are interested in chelation or nanofiltration, please call us.

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Algae

Thunderbird Pool's system of chemical care guarantees a crystal clear, algae free pool. Unfortunately, even when chemical levels are properly adjusted, algae will occasionally appear in a customer's pool. Algae comes in a variety of forms, and appears for a variety of reasons.

WHAT IS ALGAE?
Algae is an aquatic, plant-like organism. It is introduced to pool water as an airborne spore. There are three main types of algae:

GREEN ALGAE, or chlorophyta,
Green algae is the most common of form of algae. It appears as a streaky, slimy buildup, first noticeable on steps, in corners, and on the plastic surfaces of skimmers and return fittings.

YELLOW ALGAE or phaeophyta
Yellow algae, also known as brown algae or mustard algae, has the same slimy texture as green algae, but it is more difficult to remove. Yellow algae loves shade, and will often appear in covered pools. This form of algae grows in a long, streaky pattern, appearing on pool walls, in corners, and on steps and love seats.

BLACK ALGAE or cyanophyta
Black algae is the least common form of algae, but once it blooms in a pool, it is extremely difficult to eradicate. Black algae is usually the result of chronically low chlorine levels: it is often found in leaky pools, where near-daily replenishment of the pool water is necessary. As hundreds or thousands of gallons of fill water are added to the pool, chlorine and stabilizer levels drop, allowing black algae to gain a footing.

Black algae first appears as small specks, often at the deepest part of the pool, These specks rapidly develop into large, dark blue to blue-green colored buttons, slimy to the touch and virtually impossible to brush away. Untreated, black algae will quickly spread across the entire surface of the swimming pool.

Another pool problem, Pink Algae, is not an algae at all, but a bacterial growth. It is slow to grow, and is easily killed by chlorination.

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What causes Algae?
Algae spores are everywhere: these microscopic single-cell structures are blown into the pool by the wind, washed into the pool by rainfall, or carried into the pool on swimmers' skin or bathing suits. Under the right conditions, tiny spores will bloom into those dreaded bright green, mustard yellow, or blue-black discolorations.

Here are the key factors in algae growth:

• Algae can develop when little or no chlorine is present. Over time, heat, sunlight, and water loss will drive down chlorine levels. The lower the chlorine level, the more likely that algae will bloom. High water temperature is a common problem in the Gulf coast climate. Weekly chlorine "shocking," coupled with application of stabilizers designed to shield residual chlorine from the effects of heat and sunlight, helps ensure that there is always sufficient chlorine in the pool. Spas, which are often heater to temperatures well above 100 degrees, are especially susceptible to algae growth.
• Yellow algae thrives in shade. Covered pools are an inviting place for certain strains of algae. If you cover your pool, you can help minimize algae growth by periodically pulling back the cover, affording the water some sunlight and circulation.
• Algae loves a dirty pool! Leaves and dirt offer a great growth medium for algae spores. The longer you allow leaves and other debris to sit on your pool floor, the more likely that you'll see algae. In an extremely dirty pool, algae will continue to bloom, even when residual chlorine levels rise as high as 8 to 10 parts per million!
• Inadequate filtration will lead to algae growth. Water clarity depends on daily circulation and filtration. Anything that impedes water flow from the pool to the filter -- clogged skimmer baskets, a dirty or damaged filter, a defective pump motor, or a failure to run the pump for an adequate amount of time each day -- will encourage algae growth. The first warning sign of a filtration problem is hazy, milky water. Left unchecked, cloudy water can quickly lead to a full-fledged algae bloom.

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How to Prevent Algae

1. Immediately after using the spa, turn the valves so that the pool water will flow into the spa for 20 minutes. This will replenish chlorine-dissipated spa water with chlorinated water from the main part of the pool.
2. Remove your pool cover one day per week to allow the water to "breathe".
3. Check water circulation. Clean or backwash your filter if necessary.
4. Make sure the pump timer is set to run for an adequate amount of time -- 4 to 5 hours each day in the winter, and 10 - 12 hours daily during the summer months.
5. Call Thunderbird Pool Service -- we'll dispatch a troubleshooter to double check chemical levels and, if necessary, re-treat the pool! There is never a charge for troubleshooter services!
6. Make sure your filter is clean and your return lines have strong water flow.

Some spots of dead algae may remain on your pool walls, even after chemical treatment. Brushing the pool walls with a nylon bristle pool brush will remove dead algae, and help keep live algae from forming.

IF YOU GET ALGAE, DON'T PANIC!

Algae is always curable!

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Avoid 'Green Hair'

THE PROBLEM:
Occasionally blonde swimmers have a problem with hair discoloration after extended swimming. The hair takes on a greenish tint, which is blamed on everything from rusty pipes to hair color preparations to chlorine. The cause is actually copper oxide.

Copper can be introduced to the water in many ways. The primary sources are:

1. Trace copper in the water supply
2. Copper bleed from brass pumps or piping, copper fittings or piping, or gas heater coils (which are solid copper)
3. Residues from copper-based algaecides.

As these tiny amounts of copper react to chlorine in the pool water, copper oxide is formed. Copper oxide has a blue-green appearance: it's the stuff that builds up on bronze statues and metal roofs.

Actually, this problem is not unique to blondes. If copper is present in the water, copper oxide adheres to hair of any color. It is usually only seen on blonde or light red hair because other hair is too dark for the deposit to be visible.

THE SOLUTION:

As far as the immediate hair problem is concerned, a rinse or shampoo with a slightly acidic pH will strip the copper deposit from the hair. Many drug stores carry commercial shampoo or cream rinse preparations for this purpose. If they are not available, an effective home remedy is to use lemon juice or vinegar to rinse the hair. "Green Hair Syndrome" can be prevented by regularly applying a chelating compound to the water. "Metal Out," "Metal Magnet," and "YR-17" are all examples of chelating compounds. Contact Thunderbird Pool Service for more information.

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Avoid the 'Black Plague'

THE PROBLEM:

A common problem with fiberglass pools is that after aging they may begin to suffer from the "black plague".

Most fiberglass pools are coated on the inside with a clear layer that is called "gel-coat". This layer protects the fiberglass material from exposure to water, pool chemicals, UV light, etc. Depending on the thickness and quality of this material, it may begin to wear down after time. As tiny, invisible "pinholes" develop in thinner, older gel-coat, water and pool chemicals can react with cobalt in the fiberglass mixture to form a cobalt crystal. The appearance of these crystals has nothing to do with the pool cleanliness, sanitizers used, or other water chemistry. It is strictly related to the product/materials of which the pool is composed.

Once these cobalt spots have begun to form, they become visible to the eye as a dark brown or black crystal, about the size of the head of a pin. If left alone, they slowly grow in size, and they start to develop a "rust" ring around them. If on a vertical wall of the pool, this ring then streaks 1/2" to 1" down from the crystal.

THE SOLUTIONS:

To remove these crystals, you can scrape them off with a butter knife or a putty knife. The " rust" ring can be removed with a rubbing compound, or with a mild muriatic acid/water solution (start with about 1 part acid to 10 parts water, and slowly strengthen if needed.)

For an intermediate-term solution, commercial preparations specifically formulated for this problem are available at most pool retailers. They carry a variety of brand names, containing the word "cobalt" coupled with such words as "remover" or "cure". They are usually very effective in the treatment of cobalting, and most can be used in maintenance doses to prevent further buildup. If the problem is especially severe, standard chelating agents may also help.

The long-term solution is for the pool interior to be re-coated, with newer coatings that usually do not have this problem. This is, of course, an expensive undertaking, reserved normally for only the most severe cases.

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