in urgent need of help on stains on plaster from cleaning with 8.5% bleach

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bpascente

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Aug 31, 2016
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Chandler arizona
> Hi, I am in desperate need of help. I don't know how to use this site so that I can start a thread. I drained my 10k gallon in ground plaster pool 15 years old, to a pool light. I have been fighting black algae for 3 years in summer. So while pool was drained. I used a large sponge and washed the walls and floor of pool with 8.5% straight b;each. After a couple mins., I got black stains all over the plaster. I also washed out the wet niche with bleach as well. I started seeing the staining b4 I got the whole pool washed down, so I hosed down walls but no luck. Can you help me to post this so possibly someone can tell me what might have happened and what to do about correcting this staining? It is dark now otherwise I would take some pictures.
>
> Thank you, very depserate,
> Bob
 
Hi Bob! :wave: Since it's getting dark there now, probably the best thing to do is start fresh tomorrow. I'd focus on the following:
1 - Post a full set of water results from your TF-100.
2 - Tell us what chemicals you typically use in your pool and especially how do you chlorinate.
3 - Run the following tests to see if there is any change in the staining:
a. Place a chlorine tablet on the area for a few minutes (organic) - but I'm not real optimistic on that one; might make it darker (copper)
b. Try some Vitamin C tablets (crushed) in a sock and hold them there for a while (to ID iron)
c. If you have any dry acid, try some of that in a sock as well (to ID copper) - this one I'm concerned about
4 - Lastly, how does the plaster feel in those areas (smooth, rough?)

Also, have you added any pool store products to the pool like algaecides by chance?

Report back tomorrow with all of this and we should have a better direction forward. We'll put our heads to together and try to help.
 
thanks for your quick response texas splash........I drained my pool so there is no water in it. The I started washing the walls and floor with straight 8.5% bleach. Since this caused the staining in a matter of mins., I am now immediately filling the pool again with water to try and dilute the bleach (used 1/2 gallon in total cleaning walls). Yes, I have been using metal algaecides (both silver and copper) in my pool this summer to try and eradicate recurrent spots of black algae for 2-3 summers (Lays at rest in cool winter months). I drained my pool today for 2 reasons. the first was to change out a pool light which I was unable to do with it filled (could not get the proper leverage to pull old wire) and 2, to clean every nook and cranny of my pool with bleach in order to start using the chlorinating methods on this site. When I fully drained the pool, I was able to pull the old pool cord out with a new wire I attached to pull the new light in. Before I pulled the new light cord in, I decided to scrub the Niche, the walls, floor of pool, etc. Got about 1/2 the pool scrubbed before I noticed the black staining coming thru the plaster. Any idea if this is fixable, or have I just ruined a 25k$ pool?
Bob
 
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James, Thanks for your quick responses.....If I acid wash, will it remove all the metals in the plaster an gunitte since it is porous? Is filling my pool immediately now, the right thing to do, or will it not affect the staining? I still need to pull the cord on the new pool light, and will need to re-empty the water again B4 I can do that.
 
An acid wash should remove the stains but it will remove plaster layers as well.

The deeper the stains, the more plaster you need to remove.

Filling the pool won't remove the stains unless you can do an ascorbic acid treatment to remove the stains and then drain to remove the metals.

Try some ascorbic acid on a spot to see if it works.
 
Acid washing removes stains by taking a layer of plaster with them. It is my understanding that it doesn't really go after the stain itself. If it does at all, it is more incidental, than intentional. So, if you acid wash, you will be left with a rougher feeling plaster, and you will shorten the life of your plaster (because you just removed some of it), hastening the day that you'll need to replace it. Additionally, if you don't know what you're doing (like how to prepare it, how to apply it, how to rinse it, how to neutralize it, and how to pump it out, all while not burning your skin or your eyes or your lungs), you can very easily destroy your plaster all together. I just had to replace my plaster because some pool professionals messed up the acid wash they talked me into, no joke. Pardon me for saying, but you're here because you mis-applied a chemical to your plaster. I'm just saying, proceed with great caution!

Is there nothing that can be used to negate the metal staining that would not attack the plaster? Let me see what my stone guy says...
 
Hi Dirk,
Yes, I know that acid washing will etch the plaster away....I had that done 3 winters ago hoping that would remove any black algae roots that may have grown under the plaster, but no such luck....and it wasn't a great acid wash at that. And I would NEVER deal with that much Muriatic acid on my own....As we speak, I am coughing up a lung due to the amount of chlorine gas I inhaled this evening washing my pool walls....So as a result, it is already rougher than it was.....Also had a rebar wire twist stain removed and patched at the same time. My pool is going on 15 years and I guess I have to face the fact that I will need to resurface, but not with plaster again.....I need to find something more forgiving to black algae and stains. I wish they still had fiberglass in the phoenix area, but have not for many years. Thank you again and have a good night.
Bob
 

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You might be able to use ascorbic acid or sulfamic acid on the stains while the pool is full to get the metal into the water.

Then, you drain and refill to remove the metals.

Maybe go with a pebble finish when you replaster or consider ecoFINISH aquaBRIGHT.
 
bpascente said:
Hi Dirk,
Yes, I know that acid washing will etch the plaster away....I had that done 3 winters ago hoping that would remove any black algae roots that may have grown under the plaster, but no such luck....and it wasn't a great acid wash at that. And I would NEVER deal with that much Muriatic acid on my own....As we speak, I am coughing up a lung due to the amount of chlorine gas I inhaled this evening washing my pool walls....So as a result, it is already rougher than it was.....Also had a rebar wire twist stain removed and patched at the same time. My pool is going on 15 years and I guess I have to face the fact that I will need to resurface, but not with plaster again.....I need to find something more forgiving to black algae and stains. I wish they still had fiberglass in the phoenix area, but have not for many years. Thank you again and have a good night.
Bob
Click to expand...

I haven't been here all that long, but I haven't heard any TFP teachings that use metals to solve for black algae. Which leads me to believe you're not adhering strictly to TFP methods. If a new pool surface is in store for you, you'll find TFP will help you through that, and subsequent pool care that will virtually eliminate the environment friendly to black algae. More to the point, you don't need to shop for a black-algae-proof pool surface. You can get what you want and just learn to take care of it properly so that you never get BA again.

Or if you stretch this current surface for some number of years, TFP can help you get rid of the algae and then maintain your pool so it never comes back.

Have you ever given TFPC a shot, to see if it can work for you? I think it's safe to say that what you've been doing isn't working, so why not give TFP a real try?
 
James, so you believe that I may be able to leach the metals out of the plaster with ascorbic or sulfamic acid and may get the stains out and save my plaster? That would be worth a try at this point to avoid a very costly resurface. Where would I find info. on how to use and the process to follow? And BTW, where are you located in the US? Are you in a desert?
Bob
 
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Dirk, Yes that's what I was attempting to do by draining the pool, hitting every area including light niche with bleach to eradicate the BA and then start the TFP process as the process I have been taught by pool stores eventually stopped working. Too bad I did not know that the algaeside metals would adhere to the plaster and would cause this staining while I was trying to "TCP" my pool. I would have NEVER done this.
Bob
 
bpascente said:
Dirk, Yes that's what I was attempting to do by draining the pool, hitting every area including light niche with bleach to eradicate the BA and then start the TFP process as the process I have been taught by pool stores eventually stopped working. Too bad I did not know that the algaeside metals would adhere to the plaster and would cause this staining while I was trying to "TCP" my pool. I would have NEVER done this.
Bob
Click to expand...

My pool may have had BA before I replaced the plaster. I was quite worried about it reoccurring (maybe lurking in the pipes, who knows, I didn't!). But a TFP expert assured me that BA can't really take hold if you keep the water properly sanitized (which is at the core of TFP teachings). So that's what I'm doing, and so far so good. If I ever did get BA, TFP has a solution:

Pool School - Black Algae

I'm still waiting to hear back from my stone guy about how he'd go after the stain. I'll let you know if he comes up with anything.

By the way, it can be harmful to plaster, especially old plaster, to be out of the water for a length of time. It has a lot to do with just the weight of the water, which in some cases is all that's holding aging plaster in place. Your plaster can develop blisters while empty, and even after you've refilled it. Mine did both, and it was only six years old. I believe it was a combination of a history of inadequate water balance, a bad acid wash, and being out of the water. So be careful emptying your pool. It's not without possible consequences...
 
Hi again Bob. Just catching up on the discussions this morning. I found this post from a similar issue back in 2013 when someone else's plaster turned black after using a chlorine product:
From a TFP plaster Expert: The stain is probably copper, which turned black (copper oxide) on the surface after you added the chlorine shock.
I suggest purchasing some "potassium alum" granular (two or three pounds) and sprinkle it over the staining. It should remove the black stains very quickly. Vacuum to waste any residue on bottom after that, or clean filter a day later.
Click to expand...
I suspect that between the crushed Vitamin C tabs, some dry acid, or the product in that quote from 2013 you'll see a reaction to the stains. Or as JamesW noted, try some of that Magic Jack's. Either way, we'll be watching to see what develops. Hang in there Bob and try to have a good day.
 
Can you post a picture of the stains so we can see the degree of coverage/staining?

The black can be oxidized copper OR silver, which also turns black. Re-adding the water and following a Jacks Magic treatment for copper is the most promising route to go, I suspect. In addition, I've had luck with direct application via a dispensing dishwashing wand of sequestrant such as Metal Magic.
 
Texas splash, Thank you for the ideas and research. I have nothing to lose at this point. Today will be about posting some pictures, pulling the new pool light and refilling the pool. I will research the products mentioned and give them a try.
Bob

- - - Updated - - -

Hi swampwoman,
thank you for the feedback. I will post pictures later today after I have the new pool light pulled and installed. Looks like a few of you all have the same advice. Thank you,
Bob
 
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