Pool Guy Says I Have Black Algae

by Tasi Farquhar

Thanks so much for replying to my email. In Dec. 2013, my pool was refinished with a product called Sunstone Cove as well as a small glass tile under the lip of the pool. Last May I noticed that there was "algae" in tiny places and tried to clean with chlorine. I told my pool attendant about it (he comes every week) and over the summer he didn't seem to do much (we are not here in the summer).

In Nov. of 2014, I again told my pool guy to please get rid of the algae. I have to assume that he really doesn't know much about it as the algae has spread and I know I have to get rid of this before too long. Can you recommend someone in Bradenton/Sarasota who can treat this issue? I thought you might have a network of like-minded professionals.

Hello and sorry for taking a couple of days to get back to you. I been very busy with work and kids. My wife went to Daytona for a couple of days as well. Concerning your issue, I've only been in FL for a couple of years and don't know of any good pool guys in your area.

Black algae can only be contained, not eliminated. The way to contain it is the pool guy needs to first scrape the heads off. Black algae digs into the plaster and can reappear later on. Then he needs to get a chlorine tab holder called Algae Be Gon and scrub the affected areas. Then superchlorinate a couple of times which means bring the chlorine level up to 12ppm using liquid chlorine. This is the way I took care of the customers on my pool route in AZ.

I took care of many houses for Winter visitors in AZ so I know trust is a big issue when you're not there for 5 - 6 months at a time. Perhaps you can have a neighbor check in each week to give you an update.

Hope this helps.

If you feel your situation is more complex than this, I do phone consultations for a donation of your choice. It makes things go much faster and many people have found it extremely beneficial, saving them time and money in the long run. All your questions will be answered. I have nothing to sell you so you know I'm not bias.

Pool Consultation

Hope this helps and have a great Summer.


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by Vicki
(Naples, FL )

What is the green paste inside the pleats of the filter. The cleaner doesn't seem to get it out. I have not tried soaking the filter in cleaner yet. will that soften it and wash it out? Had some green algae a year ago and a little yellow now and then since.

Thanks for the question Vicki

I'd like to have your complete chemical readings, the actual numbers:

Chlorine, CYA (cyanuric acid/stabilizer), pH, Alkalinity, Calcium Hardness, and Metals (iron and copper) and names of any algaecides you may have used along with clarifiers, phosphate removers, and/or flocs. It makes troubleshooting much easier.

When the chemicals are balanced correctly your chances of getting yellow or green algae decrease tremendously. You could have an algae issue or possibly the cartridge is simply worn out. I just ordered a new cartridge filter for the neighbor's pool I take care of. I also live in FL so the pool never gets closed.

Cartridges last between 2000 - 2500 filtering hours. Divided out for 365 days and you get 5 - 6 hours per day so they're pretty much shot after 1 year.

Let's say your filter is good and there are no suction or return side issues. Then we need to look at the chemical readings. You may not have enough chlorine to kill the algae faster than it can reproduce or perhaps the chlorine has been rendered ineffective due to high or low CYA. When I get the readings we can take the right course of action to getting your pool up and running properly.

To post a reply, or if you have a similar question, you can see your post on the Q&A page in the "Cartridge Filters" category.

Check back to this post for updates or answers.

If you feel your situation is more complex and want immediate assistance (within 24 hrs) you can make a donation of your choice and I'll answer your questions by phone.

Have I helped you find a solution to your pool problems? Did this information help you? Please consider making a donation to help keep this site going. Thank you.

Have a great Summer.


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