How To Get Nasty Black Algae Out Of Pool?

by Debbie
(Weatherford, TX, Parker)


I have always had a clean pool!! We clean our filters regularly, test it, shock it, etc. We sometimes take water sample in the pool supplier just to make sure our test kit is working properly.


I noticed one day on the test kit it showed my pH was real high. So I took in a sample and they told me to add (it's like baking soda), acid, 6 packets of shock. So I came home put it all in and noticed that where I had mixed and pour in my shock it was black long wide spot.

So I brushed it and it lightened up and I told them what it did and they said wait a week and shock it again. ph was still high. So I did the same thing again well it turned black in a different spot where I poured the shock.

So they told me I had black algae and to pour in black algaecide and brush brush! So I did that and it lighten up those spots and some disappeared but now it's up the side of the steps on 2 of the steps and all in the spa.

We have the pool running 24 hrs a day for 3 weeks now. I'm so tired of messing with this.

I'm not sure if I'm doing the right thing or what even caused this to begin with. Please can you help?




Thanks for the question Debbie

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 and the process of clearing up your pool will go much faster.

You can do a very simple test to determine if you have black algae. Take a chlorine tab and put it on the affected area for about 3 - 4 minutes. If it fades you have black algae and need to take care of that.

If it doesn't fade or gets darker, get some ascorbic acid (Vitamin C tablets, about 1/2 lb.) crushed them up in a sock and put them on a black area. If that makes it fade you have metal stains and need to do an ascorbic acid treatment.

Black algae won't be removed using an algaecide. Unlike other kinds of algae this one has layers like a scab. It digs into the plaster so scraping it off with a wire brush is necessary.

You'll need to shock the pool, scrape the area with a wire brush and a chlorine tablet, all within the same time frame. You can't shock, then come back a week later and scrub with the brush, then a week later rub the area with a tablet. It must by one after the other.

This is why black algae is so bad. It takes alot of work to get it out.

Get back to me with the chemical numbers and I'm sure I can help.

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

Check back to this post for updates or answers.

If you need immediate assistance (within 24 hrs) or for emergency personal assistance, you can make a donation of $35 per hour 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.









Hope this helps and have a great Summer.

Robert

Click here to post comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Black Algae.

Is This Black Algae?

by Roohollah


We have recently encountered a problem which seems that it could a black algae. We brushed it very hard and vacuumed it but it did not work.

Moreover, it is going to spread out some other our in ground concrete pool. Therefore, we are writing to get help from you that how we should remove this stubborn algae?

Apart from that, we thank you for providing an extremely beneficial web site for us to learn more.

I am looking forward to receiving your response

Yours Faithfully,

Roohollah




Thank you for the question and compliment

First you need to determine if it is black algae (organic) or some kind of staining (metals). This is very easy to do. Get a chlorine tab and put it in a sock.

Put the sock directly on a black spot in the pool for about 15 - 20 minutes. Use a telescopic pole to hold it in place. If the stain fades, it's black algae. You can go to these links on how to get rid of black algae:

Black Algae

Is There Ever An End To The Black Algae Saga????

That Damn Black Algae

Basically you'll need to shock the pool and scrub the spots with a wire brush. Black algae attaches itself to the plaster in layers. This is why it's one of the hardest to remove. It can be done, I've personally done it, but it can be a pain.

If it doesn't fade, get ascorbic acid (crushed up Vitamin C) and put about 1/2 lb. in a sock and put that on the spot for 15 - 20 minutes.

If that fades it's a metal/mineral staining problem and can be solved with an ascorbic acid treatment. This page has the ascorbic acid treatment:

Brown Algae Won't Come Off Of A Vinyl Liner

I'd like to have your complete chemical readings:

Chlorine, CYA (cyanuric acid/stabilizer), pH, Alkalinity, Calcium Hardness, and Metals (iron and copper).
It makes troubleshooting much easier and the process of clearing up your pool will go much faster.

You can get this done at your local pool store. It might be something else entirely and the readings might give a clue as to what it is. It might not be algae, but something else.

Hope this helps and have a great Summer.

Robert

Click here to post comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Black Algae.

Swimming Pool Liner Wrinkles and Black Algae Problems

by Connie
(Canada)

Bad swimming pool liner wrinkles and black algae problems. We have an onground pool. 16 X 32 X 4 ft. 2ft are in the ground, 2ft above.

Our pool is called a Woody with a vinyl liner and a Styrofoam bottom between the liner and the sand underneath. We have a salt water system and for the first year everything was wonderful, but last year our liner came off the track and we had to call the installer in to fix it to the tune of 300.00.

Also there are a LOT of long lines of wrinkles in the pool and some very deep crevices where the Styrofoam bottom has gobbled up the liner or where the Styrofoam edges meet. My tale of woe is, last year, I noticed black in the crevices and all along the creases.

My husband convinced me it was dirt, not black algae. I think it is black algae because I had some in all around my skimmer as well and when I touched it to try and remove it, it was sticky.

I tried everything I could think of, even a tooth brush between my toes, to try and get rid of this black stuff. So, my husband closed the pool at the end of last season convincing me the cold would kill this off. Not so.

This year when we opened the pool, I wanted to remove all of the water and get in there with some cleaning products and a brush and just scrub it all off the bottom of the liner. The guy who installed the pool warned me to not remove all the water and just head over to my local pool store to get help with this problem.

We had no idea that you had to use a pool closing kit when you close the pool and another pool opening kit when you open the pool. We understood that when you have a salt water pool, all you need to do is put in salt and the salt generator takes care of the rest.

The pool store has sold us about 300.00 worth of chemicals so far.

They are telling us we need to use granular chlorine in our pool, so we added it, some whammo, so we added that, also these blue puck things in our skimmer so we did that and some other product they want us to bird feed on top of the water 20 minutes before using to get chlorine in the pool.

My husband said we are stuck spending money to add more and more chemicals because we should not have messed with it in the first place.

I know this is long, but we didn't have any problems until we installed a heater last August. Before that we always had a clean, crystal clear pool.




Wow Connie

That was one of the best, and longest, comments I've ever had. I'm not sure if you were venting or want some advice on your swimming pool liner and possible black algae issue, but here it goes. Concerning your liner, the two major causes I see with wrinkled liners are an improperly cut liner that doesn't fit the pool design or improper installation of a correctly cut liner.

For the bad fit it is a matter of taking precise measurements and ordering from a reputable manufacturer. If there are only a few small wrinkles, you may be able to remove these by using a toilet plunger. By plunging around the wrinkle you can spread out the liner in that area thereby removing the wrinkle.

Do not plunge directly on the wrinkle but rather just above, below, or to the side. You can also try to heat the pool to 92 degrees or higher to soften the liner. Push a rubber broom or squeegee along the wrinkles to smooth them out. If they are too numerous a pool professional should be called. If the wrinkles were caused by his poorly laid liner, he should come back to fix it.

Allow him a second chance to correct the problem. Now, you black algae issue is something else. Without going into too much detail, your best bet is to go to these pages:

Black Algae

Remove Swimming Pool Algae

The above links will give you the information you need to clear up your swimming pool black algae. This is really not something to be taken lightly. Black algae can ruin a pool because it burrows into anything it can find. I must point out that black algae is more common in plaster and concrete pools and is uncommon in vinyl liner pools.

But that doesn't mean you don't have black algae. Your best bet is to get a qualified pool tech to look at your swimming pool to either confirm or deny that you do have a black algae issue. Thanks once again for the questions and comments.

Robert

Click here to post comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Black Algae.

Black Spots On Pool Walls...Inground Swimming Pool

by Ed Mawson
(Wichita Falls, Tx USA)

I had my pool resurfaced inside and decided to change system to salt water generator.

I have tried direct rub of clorine on spots no such luck.




Thanks for the question Ed

More than likely it's a case of black algae which is the hardest type of algae to get rid of.

You can go to this link to learn how get rid of it:

Black Algae

If you could give a little more detail as to what you've tried, what your chemical readings have been before and after this happened, salt level, kind of salt water chlorinating system, etc...I could give a more detailed answer.

Hope to hear from you soon

Robert

Click here to post comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Black Algae.

Help With Black Like Tar In My Pool

by John
(Clifton Park, New York)

My pool was opened the last week in April.

It seemed to take a while to clear due to alot of rain from what I thought.

My pool is curently clear and all levels are spot on, bt I got a new pool vacum brush today and it was covered with black like tar.

I also dove into deep end and checked it with my hand it some black came up.

Wondering whats going on.

Do I have black algae?




Thanks for the question John

It might be a couple of things.

First, do you have an above ground vinyl liner and did you use an algaecide? You may have what's known as "pool tar" or "pool goo".

You can go to this link to check out the information:

Sticky Pool Algaecide On Vinyl Liner

I walked a guy through that and helped him clear up his pool.

Next, and I hope it's not, but it could be black algae.

Black algae is one of the worst to get rid of because it's somewhat chlorine resistant and needs alot of work to get rid of it.

Here are links to help with your problem, if it is black algae:

Is There Ever An End To The Black Algae Saga????

Swimming Pool Liner Wrinkles and Black Algae Problems

And the black algae page on my site:

Black Algae

Black algae sometimes looks and feels like scabs. This is because it basically has an outer shell and layers and digs in deep.

The above links will walk you through how to get rid of it, but be prepared to work at it.

I've cleared up several pools with black algae so I know the work involved.

Be patient. The Summer is still young and there's alot of swimming to do.

Best of luck.

Robert

Click here to post comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Black Algae.

Grey Algae On Vinyl Liner

by Sally
(Spain)


We have a french swimming pool which has a liner and we have algae growing along one wall and on the bottom round the wall. I am attaching a picture.

If it is black algae, how do we solve the problem - to further complicate things, it is a salt system.

The water is clear and we can brush it off but it starts again/ We use oxygenating disinfectant tablets each week help keep it clean.




Thanks for the question Sally

A salt water system should pose no problem in clearing up your pool. First we need to determine what the stain is, either organic or mineral. This will tell us how to approach your pool.

Go to this post:

Brown Algae Won't Come Off Of A Vinyl Liner

It will tell you how to test the algae/staining with a chlorine tablet and ascorbic acid treatment.

If it is staining, the ascorbic acid treatment will work. Directions can be found in the above link.

If it's organic (algae) you can go to this link:

Green Pools

Your pool may not be green, but the above method will work.

I'd like to have your complete chemical readings:

Chlorine, CYA (cyanuric acid/stabilizer), pH, Alkalinity, Calcium Hardness, and Metals (iron and copper). It makes troubleshooting much easier and the process of clearing up your pool will go much faster.

You can get this done at your local pool store or use a good test kit.

A Taylor FAS-DPD K-2006 pool test kit is one of the best.

Pool Water Testing

Water Testing Kit

Black algae normally doesn't happen on vinyl liners. It can, but it's uncommon. It usually reserves itself for plaster/concrete pools.

Algae happens because there's a lack of sanitation or improper sanitizing of the pool.

Get back to me with the chemical numbers and I'm sure I can help even more.

To post a reply, or if you have a similar question, you can see your post "Grey Algae On Vinyl Liner" on the Q&A page in the "Black Algae" category.

Swimming Pool Questions & Answers

Check back to this post for updates or answers.

Robert

Click here to read or post comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Black Algae.

swimming pool care, basic pool care, above ground pool maintenance, inground, salt water

Click Here To Learn How This eBook Can Save You TONS Of Time & Money

Click Here To Learn The Best Way To Clear Up Your Pool 

Recent Articles

  1. Rusty Iron Bolt Stain

    I have a dark brown iron stain from a rusty bolt that the kids threw in my cement pool.

    Read More

  2. How Long Does Can We Swim After Adding Muriatic Acid To Lower The pH Level?

    We added muriatic acid to our pool to lower the swimming pool pH level. I need to know how long after we added it to swim. Thanks for your question James

    Read More

  3. Foam In The Water..Swimming Pool..How To Get Rid Of..

    We have a 20x40 kidney shaped gunite pool. It was backed washed yesterday and some DE added. Pool water tested o.k. but towards the evening bubbly or

    Read More