Help - Black Algae in the Pool? What Next

texas_steveJune 1, 2008

I live in Houston, TX and have a grey plaster pool with moss rock/flagstone coping. Over the past several months, I have developed a pretty bad black algae problem.

The black algae is present in over 300+ spots (about the 1/4 dime size) and along the sides of the flagstone tile.

I have gone to several pool stores and have gotten many different treatment plans including copper, trichlor and other chemical treatments. I really don't know who to believe.

My water is relatively clear and my chemicals are is good balance (free chlorine, cynauric acid, Ph, etc.) I don;t think I have been running the filter long enough.

I realize black algae is very strong and requires a lot of scrubbing to pentrate the organism. Can a pool expert please recommend an effective treatment plan including the chemical(s) that work best?

Thanks in advance for your help.

Thank you for reporting this comment. Undo
barco

So you only see the algae on the tile and not in the pool? Is this on the coping are do you have flagstone as tile inside of your pool? I'm having trouble understanding where this is? Maybe a picture would help. And you are sure that this is algae right...?

BTW, I have Arizona flagstone and mine have natural black spots on the flagstone...they get blacker when they are wet. What you have scraps off and is a different color underneath...right. If its been an ongoing problem, you going to want to confirm this is algae and have someone look at it under a microscope...if you can.

    Bookmark   June 2, 2008 at 11:45AM
Thank you for reporting this comment. Undo
tagprod

I want to come see this. I think I can fix it.

    Bookmark   June 2, 2008 at 1:38PM
Thank you for reporting this comment. Undo
texas_steve

Thanks for the replies.

I am quite sure it is black algae. Most of the spots are on the plaster surface and can be scraped off still leaving a residual green spot and some etching.

On the flagstone tile, there are also green/blue/black spots as well.

Literally within a week, the algae problem (algae blooms/spots) has spread throughout the pool.

Ideas on treatment?

    Bookmark   June 2, 2008 at 2:02PM
Thank you for reporting this comment. Undo
barco

At walmart the sell a small sponge (6x4.5 inch) on a handle. Get a bucket with chlorine bleach and dip it in and use the bleach at strength, around the parameter against the tile.

(You can also use Muriatic acid dilluted 1:4.)

You have to get it all...if you let some slip...it will come back.

Once you are done, fill your pool to the brim, chlorinate your pool with 4-5 gallons of chlorine bleach or at least 50% more shock than the package says. Check again in 24-48 hrs and make sure you free chlorine is still at least 4 or greater. If not add more chlorine. Run your filter non stop. Wait for the chlorine to return to swim-safe concentration.

    Bookmark   June 2, 2008 at 3:02PM
Thank you for reporting this comment. Undo
barco

Once the chlorine is high, brush the plaster and all sides of your pool with a brush.

    Bookmark   June 2, 2008 at 3:35PM
Thank you for reporting this comment. Undo
barco

Also keep your pH below 6.8 while you are scrubing with the brush and high chlorine....it makes the chlorine work harder.

    Bookmark   June 2, 2008 at 4:16PM
Thank you for reporting this comment. Undo
texas_steve

Thanks for all of the replies! I am running my pump/chlorine generator on superchlorinate non-stop to try to get ahead of the problem. Brushing like crazy...

Any other good remedies?

    Bookmark   June 2, 2008 at 10:37PM
Thank you for reporting this comment. Undo
barco

You mean superchlorinate on the salt generator???....thats not going to do anything. Forget the SWCG...You need massive amounts of chlorine instantly...4 or 5 gallons of bleach. Add acid so that the pH is 6.8...which makes more Hypochlorite...and makes the pool even more "undesireable". Do all the changes at once so nothing in the pool can adapt to all the changes.

Turn the SWCG off..your not going to need it for a week.

That algae burns on the outside and protects itself on the inside....so you need to have so much chlorine in there...that even if its just barely getting to the underside of the algae that its so strong its killing it.

Your not going to hurt your pool or the water. Everything will come back in equilibrium in a week or so.

    Bookmark   June 2, 2008 at 10:48PM
Thank you for reporting this comment. Undo
muddy_water

Below is a product you can find at a pool supply and I'm sure you will be happy with the results...

Here is a link that might be useful: Black Algae

    Bookmark   June 3, 2008 at 7:06AM
Thank you for reporting this comment. Undo
texas_steve

Muddy Water:

I saw a previous post by you recommending this product and I tried to locate it in Houston. Only available at pool distributorships. Homeowner schmucks like me can;t shop there.

Can you tell me what the active ingredient is in Black Treat? I can;t tell from the label.

It looks like I can get it online.

Thanks!

    Bookmark   June 3, 2008 at 9:20AM
Thank you for reporting this comment. Undo
tresw

Barco is correct about the SWG, super-chlorinate is not going to get you anywhere close to the shock levels you need to get this under control. Black algae is the worst to get rid of because it roots into the plaster. When you scrub it off basically you're just removing the head, a small part of it remains in the plaster and it just comes right back again when it gets a chance. The key is raising your free chlorine to shock level and holding it there while you brush 3 or 4 times a day with a pool brush. Once it's gone hold the FC level for a day or 2 just to make sure.

You can refer to Ben's Best Guess chart to determine the shock level you need (based on your CYA level):

http://www.poolforum.com/pf2/showthread.php?t=365

And refer to Jason's Pool Calc to determine how much bleach you need to add to get there:

http://www.poolcalculator.com/

Don't buy a bunch of "magic cures" from the pool stores, plain old bleach will do the trick and cost a lot less!

    Bookmark   June 3, 2008 at 10:49AM
Thank you for reporting this comment. Undo
muddy_water

Steve I'm not at my store today so I can't look but Ive used it on pools and it works...Give the people at United Chemical a call they are great people and will also help you locate a source...

    Bookmark   June 3, 2008 at 10:57AM
Thank you for reporting this comment. Undo
barco

Can you tell me what the active ingredient is in Black Treat? I can;t tell from the label.

Probably either copper salts, colloidal silver or poly quats.

Most of the stuff sold to kill algae...you don't really want in your pool.

    Bookmark   June 3, 2008 at 12:08PM
Sign Up to comment
More Discussions
Remounting aluminum track for a cover in a salt water pool
I've got a CoverPools automatic cover for my saltwater...
nick_shirley
Need help with sealing gunite to rock, and black alge
Hey friends! I purchased a house last summer in Houston,...
Klint Turney
Resurfacing a Pool
We are looking to resurface our pool. Can you give...
rhondasumsky
J.L. Blodgett abandons pool project
I wanted to send along a note of caution to all members...
ctm14
AquaShield pool enclosure
I have AquaShield pool enclosure for less than two...
aquashield2
Sponsored Products
Modern Indoor/Outdoor Area Rug: Mohawk Home Rugs Frise Shag Black 8 ft. x 10
Home Depot
Hughes Sectional with Bumper (2 piece) - Bentley Daisey Yellow
Joybird Furniture
VIG Furniture - 4087 Modern Bonded Leather Sectional Sofa with...
Great Furniture Deal
Go Pet Club 53 in. Cat Tree Condo Scratcher Post Pet Bed Furniture - F2024
$90.90 | Hayneedle
Acadia Outdoor Area Rug
$22.50 | FRONTGATE
Louis Poulsen | PH Artichoke
YLighting
Honed Basalt Black Granite Vessel Sink
MR Direct Sinks and Faucets
Courtly Check Cheese Knife
$48.00 | Horchow
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™