Causes and the remedy for an algae outbreak
by Terry Arko
The last thing any pool owner wants is to have an algae outbreak during summer. Well-maintained pools should be free from algae; however, there are some things that can turn a maintained pool into a green menace at the height of swim season.
Rainstorms are notorious for bringing nitrogen into the atmosphere, which can naturally make its way into the pool and convert into nitrates — a food source for algae. When nitrogen in the air comes in contact with raindrops, it is converted to nitric acid, which will be carried into the pool. Flooding can cause mud and debris, which also carry algae into the pool. And if the power is knocked out and the pump cannot work to circulate water, things can get bad fast in the hot days of summer.
Summer is the time for backyard pool parties, and along with the increase in the time people are in the pool comes higher chlorine demand. Chlorine can be completely consumed within hours during a hot afternoon. This can lead to fast algae growth when the pool is packed with swimmers who bring dirt, bacteria, sunscreen and other organics into the water. Also, if guests bring their own life jackets, inflatables or even their swimsuits that have previously been in a lake or river, algae can be carried to the pool. If the pool is not super-chlorinated, cleaned and thoroughly brushed soon after the pool party, algae can appear rapidly.
Most fertilizers contain nitrogen and phosphorous; two main nutrients for plant growth and algae is a plant. Spring and even summer can be the time we are planting and renewing the backyard. The fertilizers used for lawns and flower gardens can make their way into the pool through overwatering or even the wind. Once the hot weather hits and chlorine demand increases, algae have plenty of nutrients to get a strong foothold.
Lack of Filtration and Circulation
Moving water is healthy water; water that is still will increase the potential for algae. It is imperative that the pool receives sufficient filter turnover time and good circulation throughout the pool during summer. The pool should filter a minimum of six to eight hours per day. Return jets should be positioned to prevent dead spots, and ensure the greatest amount of flow and movement throughout the pool. Many pool owners become concerned about increased summer energy rates; however, during summer any insufficient filtration can lead to additional cost from increased chemicals and treatment of algaecides. Filtration and circulation is vital during and after heavy swimmer loads.
What to do when the pool has become a swamp
Chlorine is still one of the most effective killers of algae so doing a super-chlorination of 10 to 20 ppm of chlorine can go a long way toward wiping out the algae. Bromine has been shown to be an even faster killer than chlorine, so choosing a two-part bromine algae system where you add the algae product and follow with a chlorine or a chlorine-free oxidizer to produce active bromine. These systems can kill algae within 24 hours. Immediately after adding chlorine or bromine algae products, it is important to follow with a clarifier to help floc and move dead algae to the filter. The clarifier should be dosed at three to four times the normal maintenance and can continue to be used throughout the cleanup process. The pool filter should be run 24 hours until all algae has cleared. Once the algae are cleared, the filter should be thoroughly cleaned. A preventative algaecide may be added to prevent additional outbreaks through the end of the season.
Wrap it up with a good enzyme
You may have seen commercials lately showing oil companies harvesting algae. And what are they harvesting it for? Oil. Algae exudes a hydro carbon and can leave plenty of oily residue behind in pool water and in the filter media. Using a good broad-spectrum enzyme after heavy algae growth can help clean the water and surfaces. Also, the enzyme will help break down any additional nonliving organic material, which could cause chemicals to degrade faster. Then proceed to your in-season maintenance program which includes:
- Shock with chlorine or use a sodium bromide algae product along with chlorine
- Follow immediately with a three- to four-times dose of clarifier
- Run filter 24 hours and ensure ongoing circulation and filtration
- Thoroughly clean filter
- Test and treat for phosphates if necessary
- Add a good preventative algaecide
- Use a broad-spectrum concentrated enzyme to clean up oil and nonliving organic debris
Now, the pool is ready for your customers to finish out the summer season with good quality water.
Terry Arko has more than 30 years experience in the swimming pool and hot tub industry. He has worked in service, repair, retail sales and chemical manufacturing. He has experience in customer service, sales and product development. His expertise is in the area of swimming pool and hot tub water chemistry. Argo is both a Certified Pool Operator and CPO course instructor through the National Swimming Pool Foundation. He has authored over 100 published articles on water chemistry. Argo is a popular speaker at many industry trade show events and currently works at NC Brands.