What Type of Algae Treatment is Needed for Swimming Pools?

Algae.  It is the nemesis of our swimming pool experience.  Nothing causes a pit in your stomach than looking at your pool and seeing an algae bloom.  Did you know once you can visibly see algae, it has been going on for days or longer?  Did you know that there are over 20,000 varieties of algae!?  We are going to talk in a general manner for the purpose of this tutorial.  As a Certified Algae Eradication and Prevention Specialist, I have learned oh-so-much from the course offered by Rudy Stankowitz of www.cpoclass.com and from his book, “How to Get Rid of and Prevent Swimming Pool Algae”..  I continue my education so I can share my newfound knowledge with pool owners like you and try to take the stress out of swimming pool maintenance.

What is Algae?

Algae is defined as “a group of predominantly aquatic photosynthetic, and nucleus-bearing organisms that lack the true roots, stems, leaves and specialized multicellular reproductive structures of plants.” In layman's terms, it is the green, yellow or black mess you see in your pool which has been caused by improper chemical imbalance, poor filtration or a combination of the two.  In even simpler terms, algae is a pain in the deep end. (Bad Dad joke alert!)

Algae is simplistic and requires a few elements to grow, survive and thrive. Those things are sunlight, phosphorus, nitrogen, carbon dioxide and, you guessed it, water.  Eliminating phosphates is a great way to either stop an algae bloom or limit it.  Phosphates are anything organic such as leaves, pollen and dust.  Phosphates are only a problem when they become a problem, but I always advise my clients to implement a weekly maintenance phosphate remover to not only help the chlorine last longer, but to eliminate having a Las Vegas buffet laid out should you encounter an algae bloom.

Green Algae

This is the most commonly found algae in swimming pools.  It is usually caused by not having enough sanitizer at some point, although brushing and proper circulation are key in prevention as well.  This algae can be on the walls and floor of your swimming pool and can cause the water to have a green tint.  In severe cases, it causes the pool to be opaque in all its greenness.  

Chlorine can be a super duper algaecide when used in a high enough dose. And I mean high.  30 ppm (parts per million) high.  Brushing, adding the right amount of chlorine, running the pump 24 hours and cleaning the filter may do the trick.  I advise adding an algaecide with the chlorine to kill the algae from the outside in by destroying the molecule or with an algaecide that tricks the algae into thinking the algaecide is food and killing it from the inside out.  Please see my blog on green pools for a great green algae removal remedy.

Yellow Algae

Often referred to as mustard, yellow or brown algae, this algae, in my experience, is typically circulation related.  This means not running your pump long enough or having a dirty filter as a couple examples.  You will notice this algae in “dead spots” where your pool water doesn’t circulate, in shady areas and a lot of times on the South side of your swimming pool.  Turning your return jets can be a simple fix.  If you were to put a sponge in your pool, ideally it should travel all the way around the pool.  If it doesn’t, that means your circulation isn’t either.

This type of algae will usually “dust off” when you brush it.  It can tend to be a bit more stealthy though and stick to your pool’s surface. Yellow algae can be the most difficult to get rid off and must be paired with an algaecide.  I am a big fan of sodium bromide as this can penetrate the diatom wall, which is made of sodium silicate.  Almost like a “water glass”.

The treatment is very similar to that of green algae, but just adding copious amounts of chlorine will not do the trick.  High calcium levels, along with little circulation are a vacation home for this type of algae.  Following my green algae removal process will also get rid of yellow algae.  All algae treatments end with a filter clean, so don’t try to skirt this crucial step!

Black Algae

Did you know that black “algae” is actually not algae at all?  It is several genera of cyanobacteria (blue/green algae) that has twisted itself into its own little “colony”, if you will.

It still needs phosphorus to survive so once again, I always suggest a weekly phosphate maintenance treatment to my clients.  

Let’s talk about heavy metal.  And no, I do not mean an 80’s hair band.  While sprinkling cal-hypo or even trichlor (including rubbing a tablet on the outbreak) can have some success, this is primarily for black algae on the swimming pool floor.  Your best bet is a metal based algaecide such as copper or silver.  Copper seems to have a slight edge over silver.  When using metals, you must be careful not to have too high of a metal level because this can cause staining.  Always follow the product’s instructions. And have the proper metal test kit or take it to your local pool pro.

White Water Mold

White water mold is not an algae or a mold, but more of a fungus.  The clinical term is “Chytridiomycota”, which is a biofilm.  It can look like heaps of white toilet paper floating in the pool. Usually if you see this, there is some decaying matter present in the system.  Like a dead rat in your automatic pool cleaner.  Pleasant, I know.  But since it is parasitic, this is usually the cause.   Remove the villain and try a metal based algaecide in the pool.  If this doesn’t work, you may have to drain.

Pink Algae

Sometimes referred to as “pink slime” is quite rare.  But it IS dangerous!  It is also a biofilm.  It can cause infections, especially in people with a weakened immune system.  It is actually Methylobacterium that attaches to the white water mold.  The pinker it is, the more that is present.

All of these are no fun.  We want to keep our pool algae free by brushing with a good pool brush, keeping our water circulating and balanced.  This ensures for a usable, fun pool and most importantly….everyone’s safety.  See you (algae-free) poolside!