I am going to sand my pool.

[Mark92677]

I have had it with this black algae. :x I have kept my ph @ 7.2 with TC up to 48 to 65, by CYA is 100 and a TA of 80 for months now. I've seen some improvement, but not much.
I backflushed my filter and brush all the time.

The only thing that seems to be working is the Barracuda. It seems to have a somewhat repetitive pattern that I can see through the algae, because it is almost gone where it is tracking, which leads me to believe that if I drain my pool and sand away the surface alittle, the algae, which is only on the walls, will be gone. It doesn't seem like it would take much sanding to remove it. It seems to be in the pours of the plaster just below the surface.

If I do sand the pool, is there any sealant that I should apply when I'm done? :?:

 

[frustratedpoolmom]

Hi Mark - welcome to the forum.
I would recommend you do a Google Search (bottom left corner) of "Black Algae" and read all the threads related to the topic for handy advice on how to tackle it.

Then visit Pool School - as there is a wealth of information there.

I take it this is a plaster pool? Are you brushing with a stainless steel brush, at least once a day?

CYA of 100 is way too high. It's simply not practical to try and kill algae and keep it away with CYA that high. Read "How to Shock your Pool".

Are you maintaining levels that high (not a good idea) until the FC holds overnight and you see no visible signs of algae? Or are you shocking that high, but letting it drop down right away? And how exactly are you testing that high?

Don't worry, we'll help you figure this out.

 

[Lershac]

and a cya of 100 is usually the highest most tests read. do a 1:1 dilution with fresh water and test again. double the result and see if your cya may actually be higher!

 

[Butterfly]

You've gottten good advice!

How are you testing?

Where do you live, city & state?

It would be helpful if you added pool and equipment info in your sig.
Directions in first article in Pool School.

Could you post a pic of the black algae?

Your CYA level (at least 100?) is killing your efforts.

We can help!

Welcome to the forum

 

[Mark92677]

Hi Mark - welcome to the forum.
I would recommend you do a Google Search (bottom left corner) of "Black Algae" and read all the threads related to the topic for handy advice on how to tackle it.

Then visit Pool School - as there is a wealth of information there.

I take it this is a plaster pool? Are you brushing with a stainless steel brush, at least once a day?
Yes. Yes

CYA of 100 is way too high. It's simply not practical to try and kill algae and keep it away with CYA that high. Read "How to Shock your Pool".

Are you maintaining levels that high (not a good idea) until the FC holds overnight and you see no visible signs of algae? Or are you shocking that high, but letting it drop down right away? And how exactly are you testing that high?
It is maintaining about 26 then shocking that high. I shock at night with pump off. I test with the T100 kit that I purchased from this website.

Don't worry, we'll help you figure this out.

 

[Mark92677]

and a cya of 100 is usually the highest most tests read. do a 1:1 dilution with fresh water and test again. double the result and see if your cya may actually be higher!

It's dropped to 90, but I tested it per instructions.

 

[Mark92677]

You've gottten good advice!

How are you testing?
With a TF100 kit that I purchased from this website.

Where do you live, city & state?
Laguna Niguel, CA

It would be helpful if you added pool and equipment info in your sig.
Directions in first article in Pool School.
Done! See signature

Could you post a pic of the black algae?
[attachment=0:2kyaapk4]PoolWallAlgae1.jpg[/attachment:2kyaapk4]

Your CYA level (at least 100?) is killing your efforts.

We can help!

Welcome to the forum

 

[waste]

Welcome to TFP!!

Mark, have you tried chlorine and vit. C on the stains?

They look too uniform to be black algae!

There is ~ a pattern to the stain, almost looks like some liquid has been dribbled across it.

A way to test for black algae is to scrape some of it with a fingernail and smear it on the back of a white business card - if the smear is green, it's black algae

 

[Butterfly]

I shock at night with pump off.

Is the pump running when you add your chems?

How long is it running after you bring to shock level?

What are you using to shock your pool? LQ, bleach, dichlor, etc?

Have you added any products to the pool that contain copper?

 

[Mark92677]

Welcome to TFP!!

Mark, have you tried chlorine and vit. C on the stains?
Yes, the chlorine FC is above 60. And what is vit. C?

They look too uniform to be black algae!
It is not necessaily this uniform all around the pool.

There is ~ a pattern to the stain, almost looks like some liquid has been dribbled across it.
Nope, no liquid. It is all around the pool walls in varying degrees.

A way to test for black algae is to scrape some of it with a fingernail and smear it on the back of a white business card - if the smear is green, it's black algae

I don't mean to sound flipint, but if I could scrape it off, I would have using the stainless steel brush that I have been using almost every day. Like I said, the Barracuda seems to be wearing the stuff off the wall when I super chlorinate as it continually tracks over it over & over & over & over again. That is why the idea of sanding the walls came to mind as the SS brush is just not getting it done. Muriatic acid does eliminate it, but I am afraid that that will seriously damage the wall making it very pourous. I would think that a very smooth pool surface would inhibit algae startup than a very pourous one.

 

[Mark92677]

I shock at night with pump off.

Is the pump running when you add your chems?
Yes, except for the shock treatment at night.

How long is it running after you bring to shock level?
The next day, the pump runs all day. Does not run at night when I shock it.

What are you using to shock your pool? LQ, bleach, dichlor, etc?
Packs of dichlor granular.

Have you added any products to the pool that contain copper?

Yes, after the black algae was already present, I added 16 ounces to prevent mustard algae growth which tends to start this time of year.

 

[JasonLion]

That really doesn't look at all like black algae to me, that looks like metals stains, except that the patterning is strange. Black algae will scrape off with your fingernail even after vigorous brushing with a stainless steel brush.

You should never add chemicals with the pump off. You need to run the pump for at least half an hour, preferably an hour, after adding chemicals.

Sanding is just as likely to cause plaster damage as an acid wash, and is a lot more work to do. Both take some skill to do correctly.

If you have been shocking with dichlor to the levels you describe your CYA level is going to be so high that you are going to have an extremely difficult time getting it back down again and are not going to be able to prevent algae from growing once the water warms up. You probably need to do a near total water replacement at this point.

 

[Mark92677]

That really doesn't look at all like black algae to me, that looks like metals stains, except that the patterning is strange. Black algae will scrape off with your fingernail even after vigorous brushing with a stainless steel brush.

You should never add chemicals with the pump off. You need to run the pump for at least half an hour, preferably an hour, after adding chemicals.

Sanding is just as likely to cause plaster damage as an acid wash, and is a lot more work to do. Both take some skill to do correctly.

If you have been shocking with dichlor to the levels you describe your CYA level is going to be so high that you are going to have an extremely difficult time getting it back down again and are not going to be able to prevent algae from growing once the water warms up. You probably need to do a near total water replacement at this point.

I just wet sanded with the finest grit black sandpaper, the kind you use for automotive work, on a small section of the wall. It not only took the black off, but it made the wall more flush instead of rippling like it was and it made it incredibly smooth. The pool was built over 16 years ago and the surface has become somewhat pourous (coarse).
No one has yet to tell me how this will damage the surface or why a smooth surface wall is not better than a somewhat coarse surface wall.

What exactly will result from a very lightly sanded pool with a very smooth surface?

How is this any different from an acid wash? This removes plaster material, just not as uniformly as sanding would.

I do know that plaster does perform better over time if it is sealed. That is why I was asking if there are any pool plaster sealants that anyone is aware of to use after sanding?

Isn't a plaster pool surface sealed with something after it is applied to a new pool?

I am just asking logical questions of people that are professionals in this field. This just seems more practical to me.

 

[frustratedpoolmom]

That doesn't look like or sound like Black Algae to me either...brushing with a stainless steel brush at that high of a chlorine level would certainly have a detrimental affect on true Black Algae.

Vitamin C, like a tablet you would ingest, buy it at the drug store. If you hold it up to the stain for 30 seconds and the spot vanishes or changes in appearance, it's likely metal. Holding a trichlor chlorine tablet to the staining - if it fades/disappears then the staining is organic but not necessarily Black Algae. Try both of these methods and report back. The fact that you've been brushing while at shock makes me lean towards this NOT being organic in nature.

Either way - whatever method you use to remove the staining - irregardless - you'll still need to replace your water to lower the CYA level.

We don't recommend the use of Copper-based algaecide - even in the occurrence of true black algae because the copper itself can cause unwanted side effects (like permanent black staining).

I am not aware of a "sealant" for pools (but that don't mean much ). I will PM a few of our surface experts and ask them to view your thread to advise if they can.

 

[Mark92677]

That doesn't look like or sound like Black Algae to me either...brushing with a stainless steel brush at that high of a chlorine level would certainly have a detrimental affect on true Black Algae.

Vitamin C, like a tablet you would ingest, buy it at the drug store. If you hold it up to the stain for 30 seconds and the spot vanishes or changes in appearance, it's likely metal. Holding a trichlor chlorine tablet to the staining - if it fades/disappears then the staining is organic but not necessarily Black Algae. Try both of these methods and report back. The fact that you've been brushing while at shock makes me lean towards this NOT being organic in nature.
I tried rubbing the walls with a chlorine tablet to no success.
I will try the VitC method, but if it is metal caused, what is the solution?

Either way - whatever method you use to remove the staining - irregardless - you'll still need to replace your water to lower the CYA level.
The CYA level has dropped to 90.

We don't recommend the use of Copper-based algaecide - even in the occurrence of true black algae because the copper itself can cause unwanted side effects (like permanent black staining).
Thanks, I will defintely take your advise.

I am not aware of a "sealant" for pools (but that don't mean much ). I will PM a few of our surface experts and ask them to view your thread to advise if they can.

 

[frustratedpoolmom]

Unless you have an SWG you want your CYA to be closer to 50.
Depending on the reaction with the Vit C, there a few things you can try. Copper staining is awful - and extremely difficult to remove. If the Vit C makes the stain vanish - the staining can be removed by doing an Absorbic Acid treatment. If the Vit C tablet makes the stain change color/appearance but not dissapear then it's probably copper - it's possible the only solution is an acid wash (I don't know of sanding is an option, I've never heard of doing that tho.)

Any idea how long have these stains been present?

 

[waste]

Mark, my bad - I thought you had read Pool School

 

[frustratedpoolmom]

I found this old post on another thread on Copper:

vitamin C is a waste of time on copper
Suphumic acid works pretty good - however dont think it is either the easiest product to get a hold of, or nicest to use

i have had good results with Lo-Chlor chemicals (http://www.lochlor.com) They are an aussie company but have manufacturing/distribution in the usa. the multi stain remover is a blend of acids and gret for about 99% of metal stain removal

If you use the Google Search feature, bottom left corner, you can read numerous threads about copper staining, some of them might hold tips for you. I'll keep looking but for sure try the Vit C first - it's an easy/inexpensive way to rule things out or give a positive indication of something.

 

[Mark92677]

Unless you have an SWG you want your CYA to be closer to 50.
Depending on the reaction with the Vit C, there a few things you can try. Copper staining is awful - and extremely difficult to remove. If the Vit C makes the stain vanish - the staining can be removed by doing an Absorbic Acid treatment. If the Vit C tablet makes the stain change color/appearance but not dissapear then it's probably copper - it's possible the only solution is an acid wash (I don't know of sanding is an option, I've never heard of doing that tho.)

Any idea how long have these stains been present?

About 3 years in varying degrees, although they are at their worst right now. The hyper chlorination has had some positive benefit though, but I've been doing it for about a month now.

 

[Mark92677]

I found this old post on another thread on Copper:

vitamin C is a waste of time on copper
Suphumic acid works pretty good - however dont think it is either the easiest product to get a hold of, or nicest to use

i have had good results with Lo-Chlor chemicals (http://www.lochlor.com) They are an aussie company but have manufacturing/distribution in the usa. the multi stain remover is a blend of acids and gret for about 99% of metal stain removal

If you use the Google Search feature, bottom left corner, you can read numerous threads about copper staining, some of them might hold tips for you. I'll keep looking but for sure try the Vit C first - it's an easy/inexpensive way to rule things out or give a positive indication of something.

How is this to be applied?