• Why is pool filter efficiency important?
• How do I know if my pool filter needs replacing?
• What is surface staining? How can I prevent surface staining?
• Why do blonde swimmers get green hair in a swimming pool?
• Why do fiberglass swimming pools develop the "Black Plague"?
• What is TDS. What is Total Dissolved Liquids?

• What types of swimming pool filters are there?
• What is a sand filter?
• What is a cartridge filter?
• What is a D.E. Filter? (Diatomaceous Earth)
• What is the best type of swimming pool filter?
• Why do my eyes sting in the swimming pool?

Why is filter efficiency Important?

Water clarity depends on three factors: proper chemicals balances, adequate daily circulation, and quality filtration. Your pool needs a combination of filtration, circulation, and chlorination to stay clear, blue, and ready for swimming.

Most pool owners understand the importance of chemical treatments in pool water maintenance. What is less understood is the vital role the pump and filter play in keeping the pool water looking its best.

Pool water is ciruclated by a small pump. This pump pulls water from the pool through the skimmers, forces it into the filter, then returns the water to the pool, via jets positioned on the pool walls. In our rainy, humid climate, the pool water is constantly exposed to mold and algae spores, dust and dirt, and other airborne or rainborne contaminants. Daily circulation allows these contaminants to be strained out of the water. During the summer months, the pump should be run at least 8 to 10 hours a day.

The filter is designed to trap small particles suspended in the pool water. These particles, called "colloidals," are what makes inadequately filtered water look hazy or milky.

A dirty filter can have a dramatic effect on circulation. As water passes through the filter, millions of tiny colloidals cling to the filtration elements. Eventually, these accumualted particles make it difficult for water to pass through the filter. A dirty filter can reduce pump efficiency by up to 80 percent. In other words, circulating your water for 10 hours a day when the filter is dirty is the equivalent of circulating the water for 2 hours a day when the filter is clean. Many times, a homeowner will find his water is cloudy and greenish, even though the chemical levels are fine, and the pump is running for an adequate amount of time each day. A dirty or damaged filter is the source of the problem.

There is a very easy way to determine whether the filter needs attention:

Check the flow of water from the retun jets. If the return flow is strong and steady, the filter is fine. If the return flow is weak and sluggish, it's time to tend to the filter. Filters are equipped with pressure gauges, but these gauges are notoriously innaccurate. As a very general rule of thumb, a rise in pressure of 8 to 10 pounds above normal operating pressure indicates that the filter requires service.

Diatomaceous Earth (DE) filters use a powder called diatomaceous earth to strain out impurities. Diatomaceous Earth is a fine powder, made from the pulverized fossils of aquatic plants. This product is very inexpensive, and readily available at home and garden centers. Each time you backwash a DE filter, you flush both accumulated dirt and debris and spent DE from the filter cannister. FRESH DE MUST BE ADDED AFTER EACH BACKWASHING! Failure to replaenish the cannister with fresh DE can cause severe damage to the internal elements of the filter.

There is a simple formula to figure out how much DE should be added to your filter. First, determine the size of your filter. Filter size is determined by the square feet of filtration area inside the filter cannister. This number is found on a specifications plate on the front of the cannister. (Most filters carry a filtration area of 36, 48, 60, or 72 square feet.) Using a one-pound coffee can, add one can of DE for every 5 square feet of filtration area. It's OK to round off to the nearest multiple of 5; the filter won't mind a tiny bit of extra DE, and after all, this is your swimming pool, not the SATs. A 48 square foot filter requires 10 cans of DE. A 36 square foot filter will function effectively on 7 cans.

Even with regular backwashing, DE filters get grimy with time. It's a good idea to have your filter dismantled and cleaned at least once a year. This affords an opportunity to check internal elements for wear, and to ensure that the filter is working at peak efficiency.

For those of you with cartridge filters, you can improve your filtering efficiency up to 50% by adding 2 coffee cans worth of Diatomaceous Earth to your filter. This is accomplished by adding the DE through the skimmer with the pump on, and stirring it in the skimmer until it is totally dissolved. Each time you hose down the filter cartridges, you'll have to replenish the DE. Even with DE coating the cartridges, it's perfectly safe to hose down the filter elements on your lawn. DE is safe for grass and plants, and as a valuable side benefit, it is an extremely effective snail killer!

What is Surface Staining?

Dissolved metals and minerals are present in every swimming pool. These dissolved solids find their way into a 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 suface 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.

• Periodically draining and acid washing the pool surface.
  
• 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.
  
• Chemical treatments, which remove minerals before they have a chance to settle on pool surfaces. 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 filtation 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 incompentent 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 short-term result is whiter, cleaner plaster, but the long term effect-- rougher, more stain-susceptible plaster -- makes the process very unappealing.

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 possibililty that metals or minerals will "fall out" of the water. The nanofilter is a portable unit, with its own pump and plumbing. It must be set up on your pool deck, making for an unattractive temporary addition to your backyard. Since dissolved solids are constantly building up in the pool water, nanofiltration must be done every 6 to 8 months.

There are a variety of chealting agents on the market. Pelican 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 invloved. For example:

One acid wash --
$125 to $600 (with accompanying plaster disintegration) + $100 water refill costs = $225 to $700
1 year of nanofiltration --

About 4 days per year, @ $100 per day = $400
1 year of YR-17 --

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 nanofiltration 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.

Why do blondes get green hair in swimming pools?

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:
Trace copper in the water supply
Copper bleed from brass pumps or piping, copper fittings or piping, or gas heater coils (which are solid copper)
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 creme rinse preparations for this purpose. If they are not available, an effectrive home remedy is to use lemon juice or vinegar to rinse the hair. "Green Hair Syndrome" can be prevented by regularly applying a chelating compund to the water. "Metal Out," "Metal Magnet," and "YR-17" are all examples of chelating compounds. Contact Pelican Pool Service for more information about chelation chemistry to remove the copper from your pool water.

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 productlmaterials 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 specifrcally 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.

TDS - Total Dissolved Solids

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 softdrinks, 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.

Common swimming pool filters are:

• Sand F0ilters
• Cartridge Filters
• D.E. Filters.

Sand Filters:

The outside of this type of filter is usually made out of fiberglass or stainless steel, and it is partially filled with silica sand. As water circulates from the pool through the filter, water enters at the top and percolates downward, leaving most of the oils, debris, and other impurities trapped in the sand, thus allowing clean water to return to the pool.

The filter is usually backwashed once per week, a process which reverses the flow of water through the filter. This lifts most of the contaminants from the sand and washes them out the backwash line, along with a volume of water. Eventually the filter becomes overburdened from minerals in the water and from the volume of debris (dirt, dead algae and bacteria, etc.) remaining in the sand, causing the sand to be hard and compacted. This reduces water flow throughout the system, and can cause cloudy water, poor heater operation, and increased wear and tear on the pump. Approximately every 3 to 5 years the old sand will need to be removed, and new sand added. If the pool is painted, the sand may need to be changed annually.

The efficiency of the sand filter, as measured by the largest-sized particle that can pass through it without being caught, is 40-50 microns. (A micron is a millionth of a meter.) In the past, more sand filters have been installed in some areas because of the supposed "ease of use" for the pool owner, but drawbacks of the sand filter include:
Longer hours of operation are required to properly filter the pool water
Filtration efficiency (compared to other types of filters) is inferior, especially in hot climates
Higher chlorine levels are usually required on pools with sand filters to help reduce the risk of the pool water turning green
Because of frequent high-flow backwashing, this type of filter wastes more water
Since homeowners rarely see the inside of the filter, and since the sand usually lasts for years, maintenance on sand filters is frequently neglected

Cartridge Filters:

Cartridge filters come in various sizes and shapes. Most of the filter canisters (or tanks) are stainless steel, but some are made of a hard plastic or fiberglass. There may be as few as one or as many as fifteen or more cartridge elements inside a cartridge filter. The cartridge elements are cylindrical, and made of a paper-like fiber. As the water passes through the elements, impurities are collected on the element material. Cartridges remove smaller debris from the water than sand; its micron rating is about 20 microns. This filter is cleaned about once a week by removing the elements from the canister and hosing it off using a high pressure nozzle.

Drawbacks for the cartridge filter include:
Most cartridge filters are for smaller pools and spas containing approximately 12,000 gallons of water or less
There is no mechanical method for backwashing these filters - it must be done by manually disassembling the filter and hosing it off weekly
The cartridge elements need to be replaced as they become old and worn: about every 2 years, which can be expensive, depending on the size, style and brand of cartridge
Pools with cartridge filters tend to develop high dissolved solids levels (TDS) faster than sand or D.E. filters, because there is no water removal via backwashing.

D.E. (Diatomaceons Earth) Filters:

The majority of D.E. tilters are made of stainless steel, with a few being made of fiberglass. The elements inside consist of a series of plastic grids covered with a cheesecloth-like fabric. A white powder, known as D.E., is added through the skimmer and mixes with the water as it heads toward the filter. As the water passes through the filter, the D.E. powder coats the outside of the elements. This coating traps microscopic impurities which cannot be trapped by sand or cartridge filters, and therefore provides better water clarity in the pool. The efficiency rating of a D.E. filter is about 3 microns. This means you can filter anywhere from 15% to 50% less per day, which results in reduced electric bills, and extended motor life.

Especially in drought areas, D.E. filters are most commonly recommended and installed because of the lower water requirements for cleaning (compared to the sand filter).

• Drawbacks for the D.E. Filter:
  To clean this type offilter, the filter must be taken apart in order to hose the elements off with water. Each time you backwash, or clean the grids, you need to re-charge the filter by adding two to four pounds ofthe D.E. powder (which is very inexpensive) through the skimmer. However, since modern D.E. filters can go as long as 6 months to a year between cleanings, this is not much of a drawback! Older D.E. filters usually are cleaned quarterly
  

What is the best type of swimming pool filter?

If you pose the questions at the start of this bulletin to someone who doesn't regularly maintain swimming pools, you might receive a wide range and variety of answers. But if you ask a trained service technician who services pools daily, and who is responsible for the cleanliness of your pool and the clarity of the water, you will consistently hear the same answer: D.E. filters (Diatomaceous Earth) are the best! If your filter is working fine, there is obviously no need to replace it, but if you are faced with the need to install a new filter or replace an old one, please consider the following points:

• All three types of filters are used within the pool industry. The warmer the pool water becomes, the more efficient the filter needs to be. Sand and cartridge filters work best in cooler climates, but in the western states, where pool water temperatures often reach the 90's, they aren't nearly as effective as D.E. filters.
  
• The cost differences between the sand and D.E. filters are minimal, with cartridge filters being the least expensive. If you are looking for dollar value without headaches, the D.E. filter will give you that and more!
  
• A D.E. filter requires less time and effort to maintain in optimum working condition. Although most problems experienced by sand and cartridge filter owners are caused by improper maintenance, even a perfectly maintained cartridge or sand filter cannot match the efficiency ofa D.E. filter.
  
• As measured by the size of particle it can remove, a D.E. filter is 7 times more efficient than a cartridge filter, and 15 times more efficient than a sand filter.
  
• A D.E. filter is the best choice for those who must keep the pool clean and clear, for those who swim in the water, and for those who enjoy the look of sparkling, crystal clear water in their backyard pool.

Why do my eyes sting in the swimming pool?

Red, irritated eyes, sometimes accompanied by dry, itchy skin, are a problem for some swimmers. Many incorrectly blame such discomfort on "too much chlorine in the water". Chlorine is not the culprit! Even in concentrations above 5 parts per million, chlorine will not burn eyes, dry out skin, or damage hair. In fact, superchlorination is often the most effective treatment for eye burn and skin discomfort. Swimmer discomfort can be caused by several factors:

• pH Imbalances
  The human eye carries a pH of about 7.2. Exposure to pH levels significantly lower or significantly high than 7.2 will irritate the eye. Have you ever tried to spoon into a grapefruit half, only to have a spray of grapefruit juice hit you right in the eye? Citrus fruits are slightly acidic -- the pH of grapefruit is around 5.0 -- so a little grapefruit juice feels just like a poke in the eye. Most soaps and shampoos are alkaline, with pH levels well above 8.4. Despite the difference in pH, their effect on the eye is the same: an eyeful of shampoo is a miserable experience. When pool water is allowed to become too acidic (6.8 or lower) or too alkaline (8.2 or higher), the result to swimmers is the same as exposing their eyes to shampoo or grapefruit juice: it stings like crazy! Over time, pH imbalbnces can also cause deterioration of pool plaster, fittings, and circulation equipment.
• Chloramine
  Under ideal circumstances, chlorine applied to the pool will bond to water molecules, forming a chemical called hypochlorus acid. Hypochlorus acid sanitizes the pool water: it kills algae and bacteria, and keeps the pool water safe and pleasant. When ammonia is introduced to the water, the chlorine in hypochlorus acid bonds to it, creating a new, unpleasant chemical, chloramine.
  
  Chloramine is an irritant, causing redness, soreness, and puffiness around the eyes, dry, itchy skin, and irritation to the mouth and throat. Since it bonds to chlorine, chloriamine compromises the effectiveness of pool sanitizers, greatly increasing the likelihood that your pool will develop problems with algae and bacteria. Finally, it produces a strong, unpleasant odor, that most people describe as a "bleachy" smell.
  
  Ammonia is an undesirable, but nearly unavoidable presence in pool water. Swimmer byproducts -- sweat, spit, urine, even hairspray, colognes, and deodorants -- bird droppings, dog waste, lawn and garden fertilizers and some "quatrain" chemical algaecides all contain ammonia. odor.
  
  Chloramine is reactive to pH levels: the lower the pH, the more pronounced the irritating effect of chloramine. Since low pH is itself an irritant, the combination of low pH and chloramine can make for an especially unpleasant experience.
  
  There's only one cure for chloramine: BURN OUT. No, we're not talking about turning on and tuning out; breaking chloramine's hold on your pool requires adding enough chlorine to "burn out" the ammonia hiding in the water. Burn out, or breakpoint chlorination, requires adding a heavy dose of chlorine to the pool. This superchlorination will destroy ammonia, eradicate chloramine, and restore a pleasant taste, feel, and scent to the pool water.
• Total Dissolved Solids (TDS)
  A third causative factor for eye irritation in swimming pools can be a high level of dissolved material in the water. An acceptable amount of total dissolved solids (TDS) may be as low as a few hundred parts per million (ppm) and as high as 2000-3000 ppm. When levels exceed 3000, the results may include eye irritation, cloudy water, and difficulties in maintaining water balance. Meters are commonly used to measure the TDS of a pool, but a do-it-yourself test is to simply open your eyes underwater. Pool water with excess TDS may be crystal clear when looking at the water from above, but when you open your eyes underwater, it is normally turbid (cloudy or hazy). If you suspect high TDS, call Pelican Pool for testing of your water.