Stains
There are two types of pools- Pools that are stained and pools that are going to get stains. There are many different types of pool surfaces available now. They fall into three basic categories- Fiberglass, Vinyl, and Concrete. Each of these surfaces can have different issues and stains specific to their type. Our certified stain expert can identify the specifics of your pool and recommend a treatment.
There are two main categories of stains- Organic and Inorganic. Inorganic stains are caused from metals and minerals that enter the pool water and then chemically attach to the surface of the pool. Brushing the pool will have no effect on inorganic stains. Organic stains are caused by tannins in plant matter or are left behind from algae.
Inorganic Metals
Iron – Rust colored shading. Often thought to be yellow algae, but it does not go away when brushed. Common sources for general staining are fertilizers, pesticides, herbicides, iron water pipes and valves, and well water. Spot staining can occur from hose ends, granular fertilizer, screws, metal shavings, etc.
Copper – Varies in color from bright turquoise to gray and black. Common sources for general staining are algaecides, copper plumbing, and heat exchangers in heaters. Spots can occur from coins, BB’s, etc.
Cobalt – occurs in fiberglass pools. These start off as small black spots and grow bigger eventually getting fingers like stars. These stains are difficult to remove on older services and can be very persistent and tend to reoccur quickly. They are moderate to remove on newer surfaces. They are due primarily from high Chlorine and pH levels for an extended time or aged surface material.
Minerals
Calcium Bleeds – White nodules, “drips”, streaks, flows or domes. Calcium will leach out of grout, pavers, and concrete. If it is above the water line it is not pool water chemistry related. These deposits continue to crystallize and will get harder and therefore more difficult to remove in time. They can be reoccurring and can be a sign of imbalanced water.
Scaling – usually calcium of some type that builds on the surface and appears as a chalky film that wont brush off. Salt pools are more prone to this. Improper chemistry can cause this. Most pools have some scale, but the newer dark surfaces show the scale where the white surfaces hide it.
Organic
Tannins – just like coffee or tea these are discolorations from plant material. The tannins soak into the pool surface and discolor it. Shocking the pool will usually get rid of these.
Green Algae – Green algae grows in neglected pools. Once killed, it can leave behind some greenish to black discoloration on the surface. These will usually go away over time or with additional shocking.
Black Algae – Black algae is not a stain but is an algae that grows deep into the surface of concrete pools. It is black to purplish in color and forms a gelatinous dome over itself that protects it from chemicals. It is very chlorine resistant and must be treated aggressively. It can grow when the surface begins to deteriorate, water has poor circulation, and/or the chemistry is unbalanced for an extended time. In poor surface conditions it will continue to reappear as its roots go deep into the surface and are very difficult to fully kill. Once killed, the discoloration will disappear.
Yellow Algae – This is also called mustard algae because it comes in all the colors that mustard comes in from bright yellow to brown. It will brush off a surface completely with little effort. Some strains of this algae are very chlorine resistant and may try to reoccur if not treated properly.
Pink Algae – This is actually a bacteria and not an algae. It is pink in color and slimy. Most commonly found inside pool plumbing it is rarely seen. It is very easy to kill and will not leave any discoloration.
Bacterial Iron – This is another bacterium that rarely forms in pools. It feeds on iron. It produces a yellow-orange film that looks like yellow algae but does not brush away entirely. If allowed to continue to grow it will form slime tendrils that can clog equipment and destroy filter elements. It should be treated aggressively and should not leave any permanent marks
Liner Mold – This occurs in vinyl pools only. This is a mold that grows under the liner in the dirt. The soil behind the liner must be treated in order to remove this. It posses no risk to bathers but it looks terrible.
Other Surface Issues
Hydration – This is also called modeling. This appears as darker or lighter spots in the surface or shading. It is usually most obvious at the joints of the steps. In extreme cases you might have a ring around the entire pool or a circle around the floor drain or even footprints. This is primarily caused during construction or the start-up of the pool. However, the discolorations won’t appear for 9 months or more after start-up. Different amounts of moisture trapped in the concrete cause it to cure slightly different colors and leads to shading.
Etching – This is rough texture and pitting in the concrete surface material. Some of the surface has actually been removed. This can be caused by age, exposure of surface to air, or aggressive water chemistry among other possibilities. These rough spots are more porous and far more likely to develop stains and algae.
Chemical Burns
Tabs – stabilized chlorine tabs (white hockey pucks) These tabs are very corrosive and should never be allowed to come into direct contact with the pool surface. If a floater is used it should not be allowed to set on the top step. It will also destroy the basket if left in a skimmer to dissolve. In-line chlorinators may also cause damage to the surface if a pool return is close to a step. Over time the continued and repeated exposure to this corrosive chemical will cause a “burn” in the surface. The surface material has been dissolved and etched away.
Acid – Muriatic acid usually is also very corrosive and should be diluted before adding it to pool water. This diluted mixture should be added in the deep end with the pool running. Acid is heavier than water and will rest on the bottom if given the opportunity and etch the surface.
Unbalanced water – Water that is unbalanced for an extended time will cause damage to your surface and/or equipment. Corrosive water will etch and damage the surface and scaling water can cause scaling and be a catalyst to metal stains.
Erosion – High velocity of water over the same area for a long time can also cause wear on your surface by erosion. Unbalanced water will cause even more damage quicker.
Stain Prevention
What can you do to minimize/ delay staining in your pool?
Water Filters / Metal traps can be used to prevent metals and minerals from entering the pool while filling or adding make up water. It may not seem like much but the minerals and metals can build up quickly in the pool. They do not evaporate and most will never be filtered out.
Sequestriants can be added to the pool water. These products make the minerals and metals clump together so that they form larger particles that the filtration system has a better chance of catching and therefore removing from the pool. There are some side effects associated with some of these products. The most common is a milky blue cloudiness in the pool. This is a chemical reaction that can usually be cleared up by adding a little bit of acid to the pool water.
Use high end pool chemicals only. You are exposing your eyeballs and accidentally ingesting your pool water constantly. Be careful what you put in there. The cheaper chemicals can contain all kinds of inert fillers and traces of metals and minerals far higher than the name brand chemicals. We only use high end name brand chemicals.
Remove debris as it enters the pool. Some of the most common stains we see could have been prevented. The fallings from palm trees are notorious for leaching tannins into pool surfaces. These should be removed immediately. Any metal that gets into the pool will also lead to staining. Metal only needs to be left on the surface overnight to leave a mark. Metal hose ends, coins, bobby pins, toys, paper clips and even the metal crimp on hair rubber bands are very commonly left in pools overnight and can leave a nasty spot by the morning. Cooper BB’s and silver jewelry are not very common but leave very nasty stains.
Use filtration aides and name brand filter cartridges. Not all filters are created equal. Cartridge filters are the most common type in use. These cartridge elements should last 12 -18 months under average use, conditions, and maintenance. The quality of material used for the cartridges is very important to how well it works. We prefer to use the manufacturer’s replacement elements and we never use the low end generic ones. You get what you pay for with filter elements. The low end filters do not last nearly as long and will not catch as small a particle as the name brand. Cartridge filters should capture particles of 25 microns or bigger. A sand filter will catch particles of approximately 50 microns or bigger (twice as large). A DE filter can catch particles of 2-5 microns or bigger. Obviously DE filters catch the smallest particle and should therefore provide the clearest water and remove metals and minerals the best. There is an additive that is cellulous (plant) based that can be added to cartridge and sand filters to improve their filtration ability to remove particles down to 2 -4 microns in size. This additive can be useful in removing oils as well.
