What causes Algae problems?
Every pool owner has, at one time or another, done battle with the occasional algae bloom. Algae spores constantly enter the pool, brought in by wind, rain or even contaminated swimsuits or equipment. When conditions are right, an algae bloom can occur seemingly overnight. These conditions include out of balance water, warm temperatures, sunlight and presence of nitrates and/or carbon dioxide. Of course, a lack of proper circulation, filtration and sanitation may be the primary cause of the algae. The best process is one of elimination.
Algae is a living aquatic creature that multiplies rapidly on warm, sunny days. Containing chlorophyll, algae utilizes photosynthesis to grow. That is, they take in carbon dioxide and expend oxygen as a byproduct.
What problems can Algae cause?
The first noticeable problem is that no one seems to want to go swimming. The second problem is that it requires work and effort and money to rid the water completely of algae. It is therefore best to use preventative chemicals and techniques, described later. Algae can cloud and color the water, making rescue attempts difficult and reducing depth perception of a diver. Algae itself is not harmful to swimmers, but pools with algae may also be harbor to pathogens like E-coli bacteria.
In addition to clogging up sanitation pathways in the water, algae also clogs up the pores in a filter, decreasing filter effectiveness and requiring more backwashing or medium replacement. Algae creates a chlorine demand in the water for itself, actually consuming chlorine that should be working on other contaminants. Algae are kind of like weeds in your garden. Unsightly, unwanted space takers that create more work for the gardener, and sap up nutrients and resources from the flora we wish to grow.
What types of Algae are there?
There are over 21,000 known varieties of algae! In the pool business we avoid all of the complication by referring to algae by the color they exhibit.
An extremely common variety, green algae will usually rear its ugly head immediately following a hazy condition in the water from a lack of proper filtration and/or sanitation. It is frequently found free floating in the water, although it also will cling to the walls. It reduces water clarity and is thereby distinguished from severe copper precipitation, which will impart a clear, green color to the water. Varieties of green algae also appear as "spots" on surfaces, particularly rough areas, or places where circulation is low. They also show up as "sheets", where large wall sections, or even the entire pool, is coated in green slime...UGH!
A wall clinging variety, also called mustard algae, is usually found on the shady side of the pool. It is sheet forming, and can be difficult to eradicate completely. Once begun, a pool owner could spend the entire season fighting yellow algae; re-infection is common. This variety is resistant to normal chlorine levels and must be dealt with firmly. Hit it hard!
Perhaps the most aggravating strain of algae, it has been compared to herpes; "once you've got it, it's there for life." This is not entirely accurate, but the difficulty in eradication is due to the strong roots and protective layers over top of the black algae plant. Black algae will appear as dark black or blue/green spots, usually the size of a pencil eraser tip. Their roots extend into the plaster or tile grout, and unless the roots are destroyed completely, a new head will grow back in the same place. The heads also contain protective layers to keep cell destroying chemicals from entering the organism. Like yellow algae, black strains can bloom even in the presence of normal sanitizing levels and proper filtration. I was once told that this form of algae commonly enters a pool inside the swimsuit of a person who's recently been to the ocean.
Not really an algae at all, but a form of bacteria. Appears as spots or streaks in corners and crevices. It is slow to spread and rare that it will bloom over an entire pool.