Why can fertilizer cause an algae bloom?

Answer 1

Algae is a plant, and wants to grow in your pool for the same reason it grows in ponds, lakes, streams and oceans. Water is it's natural habitat. Although in its simplest form, algae is not a health issue, it will lead to potential problems when it start attracting mosquitos, bacteria, etc. So the trick is to prevent it in the first place, or get rid of it as soon as you see it. Adequate (but not too much) chlorine will generally prevent algae growth, with some exceptions. One of those exceptions is the presence of high levels of phosphates. Phosphates are biologicals such as skin cells, decomposition of leaves, dirt or fertilizer blowing into pool, etc. This becomes food for the algae and allows the algae to fight off the killing power of chlorine. The advise below is assuming you have just a small bit of algae: Shock the pool with chlorine. Brush the algae off the walls and floor as best you can. Run your filter 24 hours. Brush the pool again to remove any algae missed the day before. Run your filter another 24 hours. Thoroughly clean your filters. Use chlorine neutralizer to bring chlorine level blow 5 ppm before swimming.

Have your water tested for phosphates. Treat if levels are between 250 ppb and 2000 ppb. Higher levels will require partial draining. Your local pool store can give you additional advise on shock, phosphates and tell you if it is safe to partially drain a pool in your location. Never totally drain your pool unless you know the geological stability of the ground below your pool.

Answer 2

Algal blooms are natural occurrences, and may occur with regularity (e.g., every summer), depending on weather and water conditions. The likelihood of a bloom depends on local conditions and characteristics of the particular body of water. Blooms generally occur where there are high levels of nutrients present, together with the occurrence of warm, sunny, calm conditions. However, human activity often can trigger or accelerate algal blooms. Natural sources of nutrients such as phosphorus or nitrogen compounds can be supplemented by a variety of human activities. For example, in rural areas, agricultural runoff from fields can wash fertilizers into the water. In urban areas, nutrient sources can include treated wastewaters from septic systems and sewage treatment plants, and urban stormwater runoff that carries nonpoint-source pollutants such as lawn fertilizers.

Answer 3

The runoff from farms is not pristine rainwater. During its brief residence on the

farm, it has dissolved chemical fertilizers and animal waste, among other stuff.

Algae love a lot of those things.

Answer 4

Algae are distributed by spores into fresh or marine water. Cell division of the spores creates an organism. Algae feed through photosynthesis. They are a plant.

Answer 5

It provides the nutrients that algae need to bloom.

Answer 6

not all sewage helps but the reason is that sewage holds nutrients that some plants and algae can act as a fertilizer