Phosphate is fast becoming recognized as the major cause of algae in swimming pools.
This summer has seen some of the top recorded phosphate levels in swimming pools over Australia and New Zealand. Some of this high level of phosphate has been attributed to summer drought linked dust fallout, and an growth in the phosphate levels of several common fertilizers. For many years phosphate and nitrate runoff from farms has been blamed for the deterioration of our many lakes and waterways, now the qoute has crossed into our swimming pools.
For pool owners, the biggest concerns from high phosphate levels are rapid chlorine consumption and stubborn, repeat algae problems.
Removal of phosphate from pool water is important to help articulate salutary water quality. Once it has been removed, quarterly maintenance can prevent the level from becoming a qoute again and also aid in best chlorine performance and efficiency, reduced chlorine consumption, and no algae problems.
Phosphate and nutrients are required by all living organisms, together with algae, to survive and flourish. It is well documented that raising the swimming pools chlorine level will effect in less algae problems. But how are they related, and what can be done to remove phosphate from swimming pool water?
Phosphate is introduced to pool water from a variety of sources together with runoff from lawns and gardens, pool fill water such as bores, dust, suntan oils and leaves. With time, all of these sources will cause a build-up and growth in the concentration of phosphate in the pools water.
Algae spores are continually being introduced to the pool attached to dust and leaves. They only need nutrients and water to fast multiply and come to be a threat to the pools water capability due to rapid consumption/destruction of ready chlorine.
For decades chlorine has been used not just as a pool sanitizer, but it is also efficient as a short lived algae killer.
Traditional rehabilitation has included "shock" dosing the pool with three to five times its quarterly daily chlorine dose; this is efficient at killing off roughly all visible algae.
While this effectively kills the algae, it does not do whatever to address the health that allowed the algae to flourish in the first place. When the chlorine level returns to general to algae will begin growing again.
Therefore preventing the algae from recurring requires that the chlorine concentration is maintained at the higher level, the water is removed from the pool, or water conditions are changed to come to be less favourable for algae growth.
Traditionally, phosphate levels have been ignored, while attempting to remove dead algae by filtration. Given wet algae weighs 1000 times more than the phosphate needed to feed it, this is not the most efficient way to do this. Also as the algae are trapped in the filter, it releases a inevitable whole of trapped phosphate back into the water.
The most efficient customary rehabilitation is "super chlorination" or ten times the general daily dose, effectively bleaching the algae white and killing it. This is followed by a "floc" with aluminium salts, before vacuuming the placed dead algae to waste.
Up until recently, none of the customary treatments for algae targeted the real cause of the algae problem. Chlorine has always been recognized as an efficient algaecide, however does nothing to treat the cause of the algae problem.
In swimming pools there are two efficient chemical treatments for removing phosphate from swimming pools: aluminium compounds and lanthanum compounds. In sewage and effluent rehabilitation ponds, iron compounds are used effectively, however these are undesirable in swimming pools due to the staining they cause.
Aluminum compounds are more efficient in pools with a high level of phosphate build-up, in the range of greater than 1000ppb (parts per billion); however they need vacuuming to waste after treatment. They will effectively remove phosphate down to 500ppb, but cannot remove phosphate below 100ppb which is required for efficient algae control. Aluminum compounds are relatively cheap, and therefore suitable for extraction of a large ration of phosphate accumulated in the pools water.
Lanthanum products are a potent and definite phosphate remover. They are best mighty to maintaining low levels of phosphate in pools where performance and convenience are important. They are easier to use and apply than aluminum products and do not need vacuuming to waste after their application. however they are more costly and best mighty for pools with less than 2000ppb accumulated phosphate. One of the main advantages of lanthanum is that its capability to form lanthanum phosphate is not affected by the pools water balance.
A small whole of lanthanum blend will cause the phosphate level to drop below 100ppm, while concentrations of below 10ppb are easy to maintain.
Lanthanum compounds work by lodging in the pools filter media or cartridge, gently dissolving to lightly coat the filter media. As phosphate rich water passes over the lanthanum crystals, they chemically attach themselves to the phosphate - forming lanthanum phosphate. Lanthanum phosphate is not suitable as a nutrient, and binds into larger particles so it can be removed by the pools filter medium. Lanthanum can be stored in the pools filter in large quanties without causing cloudy water.
To conclude, phosphate extraction is the incommunicable to maintaining algae free, capability swimming pool water, while allowing other chemicals to work at their optimal level.
Additional algae insurance, is the use of a preventative, "long life" copper based algaecide to be used in conjunction with quarterly testing for phosphate.
While phosphate will procure in a pool naturally, there are steps pool owners can take to prevent excessively high levels.
- Do not allow runoff from gardens and lawns to enter the pool
- remove leaves from the pool commonly and at once
- Apply a lanthanum blend phosphate remover commonly
- Have the pools water tested by a professional.
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