Black staining of my beautiful pool. HELP!!!!!!!!!!!!!!!

Jul 21, 2008
5
I've had pools my whole life, not an expert, but know enough to be dangerous at times and accidentally fix stuff at times. :) I guess everyone gets lucky from time to time.

I converted from a cholrine system to a salt water system (Aqua Rite) about 4 months ago. I've always had light colored yellow algae blooms at times...easily removing them with a brush or shock treatments. When I made the coversion from cholrine all of my algae problems seemed to have stopped, which was a relief to me.

About 5 weeks ago we had 12 or so swimmers in our pool over a couple of days. I also noticed the next day that some algae blooms were growing in the pool. Well, I decided to shock it with high grade shock like I always have, but had never shocked it with the salt water system in place. I threw my shock in and before it hit the bottom of the pool the shock turned black and everywhere it hit stained my pool black.

Yes, it flat out stained my beautiful, clean pool. Everywhere the shock ran, it turned my plaster black. I tried to brush it out with a couple of different brushes and it did not work. The stain obviously was so deep it would not come off. Well, I started looking around online and noticed Vitamin C might remove the stains that the SHOCK caused.

I took a few tablets of Vitamin C and crushed them up and put it in a sock with a rock and placed it over an area of black stain. Within 3 seconds the stains are coming off. So, I roll the sock around the shallow end and everywhere it touches the stain is lifting. That's when the light bulb in my head clicked on.

So, I decided to put Vitamin C tablets all over my pool and let them disolve at the bottom. I turned on my polaris about 30 minutes later and stirred it all over my pool and 90% of the stains came out in just a few hours. The next morning I got up to see that I still had some black areas in my shallow end so I threw a few more Vitamin C tablets on the spots to treat them. These spots were located in the area of my pool where there is a sudden drop off. The tablets started to roll to my deep end and along the way(you will not believe this) turning my pool black again everywhere they ran (like fingers reaching out).

The very Vitamin C that cured my pool of the stains 24 hours earlier turned my pool black again in seconds. I decided I'd throw shock in my pool again to see if it would oxidize the stains and sure enough the shock worked. Remember, the shock is initially what caused my pool to stain black. I ran my polaris for about a week (6-8 hours a day) and the stains lifted, or most of them.

The shock stains my pool black, the vitamin C cured it. The next day Vitamin C stains my pool and the shock cures it. What is good for my pool one day is bad the next. Yes, my pool has it's own personality. I had my water tested for metals the day it happened and no metals were found in my water. I had my water tested the next day as well and no metals were found. I had my weekly chemical check twice that week and everything was exact. All the levels were right on with a healthy pool and still are today.

Needless to say, my pool has never been the same since my unfortunate event. There is still light black staining on my walls in the shallow end. The staining is getting worse and starting to spread again in the shallow end. I tried the Vitamin C tablet on my steps in the the pool and it turned black on contact and everywhere the powder rolled turned black, too. Went up to the pool store and had my water tested and everything was fine (no metals in my water).

This is where I am at as my pool stains black again:
#1. Vitamin C (stain remover) same thing turns my pool black.
#2. Shock turns my pool black.
#3. Now, some of my walls are turing bluish greem and spreading with the black stains.

My pool supplier has never heard of such a thing. My pool man has never seen or heard of anything like, but admit anything is possible. No one can tell me how to get rid of the stains or what is causing them. I really feel I deal with some credible people that are at a loss as to why this is happening. Can anyone out there tell what in the heck is happening to my pool and how an oxidizer stained my pool black and WHY what's good for my pool one day is bad the next? I'm scared to put anything in my pool to cure the problem. My water is crystal clear.....thank goodness!

No iron or copper has been found. No one has used any fertilizer in my area. I know I've talked in circles. I'm trying to work and deal with clients. Sorry, for the butchered message.

Thanks in advance!
Swag :hammer:
 
That sounds like copper. Is there a way copper might have gotten into the pool? Common sources include "mineral" systems, copper based algaecides, and very low PH etching copper heat exchange coils in a pool heater.

A good sequestrant will probably help. I would try a sequestrant based on HEDP or phosphonic acid, such as ProTeam's Metal Magic and Jack's Magic products.
 
Thanks for the response. I did use some "metal out" to lift the color when it originally happened. Is sequestrant HEDP or phosphonic acid, such as ProTeam's Metal Magic and Jack's Magic products the same as "metal out?"

My pool supplier checked my water for copper twice. He told me that some times copper in the water means your pool heater is going out. Both test showed minimal amounts of metals and he said it was normal for pools to have a tiny trace of metal in them and not to worry. The heater was the first place I thought the copper could be coming from. But where else could the metal be coming from if not from the heater coils? My pool was last sand blasted about 8 years ago. Could the metal under the pool or on the walls cause this adversion? Just a thought! The plaster is in average shape or better. Thanks for help.
 
I think someone on here mentioned if the pool is stained, the metals have transferred from the water to the pool surface, so the water itself will only show traces of metals, if any. The sequesterant puts the metals back into the water but binds them somehow (above my head, to be sure :oops: ) so that they can't stain your pool.
 
frustratedpoolmom said:
I think someone on here mentioned if the pool is stained, the metals have transferred from the water to the pool surface, so the water itself will only show traces of metals, if any. The sequesterant puts the metals back into the water but binds them somehow (above my head, to be sure :oops: ) so that they can't stain your pool.

Gotcha! Thank you! :goodjob:
 
First let's clear up a misconception, a salt pool IS a chlorine pool--you are just making the chlorine in the cell.
Now a question. What kind of heater do you have and how old is it? Some of the older heaters with copper heat exchangers are NOT compatible with SWGs and can and will leach copper into the pool. The staining you described is a classic case of copper staining and it is NOT normal to "have some metals in the water".

I suspect that your copper is coming from your heater. IF that is the case you will need to replace the heater with one that is compatible with a SWG as your first step.

I would also like to see a full set of test results. I suspect that you also have some water balance issues.
 
DLSDO said:
Swagger,
A set of numbers might prove helpful....FC, CC, CYA, pH, TA, & CH. I am not convinced that your not also fighting an algae bloom. Does your FC hold overnight?
Thanks,

Thanks for the help and post. I have a pool service test my water and to do a chemical check every week on my pool. I work about 50 hours a week, so I have to leave the numbers task to others. I don't know the exact numbers but do know my FC struggles to hold for more than 24 hours and always has. And I have been fighting an algae bloom problem for years, but seem to always to get it under control with a few treatments until the temp gets up to 100-105 daily.(like right now) The next ten days the temp is supposed to be 100 or higher, so the fight will be on to beat those blooms back. We always get'em whipped though. Thank you!
 

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Swagger said:
Thanks for the help and post. I have a pool service test my water and to do a chemical check every week on my pool. I work about 50 hours a week, so I have to leave the numbers task to others. I don't know the exact numbers but do know my FC struggles to hold for more than 24 hours and always has. And I have been fighting an algae bloom problem for years, but seem to always to get it under control with a few treatments until the temp gets up to 100-105 daily.(like right now) The next ten days the temp is supposed to be 100 or higher, so the fight will be on to beat those blooms back. We always get'em whipped though. Thank you!
I will bet that the key to your problems is your CYA. Get your water tested and find out the numbers! I work in the industry and can tell you that most pool service companies (with a few exceptions) are pretty useless! I work 3 jobs so I understand about being busy (It's much more than 50 hours a week!) but if you don't want to take control of your water then you are not going to be able to fix the problem. It might sound harsh but it's the bottom line. You yourself said that you have been struggling to hold FC and been fighting algae for years. You can put an end to these problems now but you have to take control of your water yourself. Otherwise, just accept that your service company is not doing a good job and live with it.
 
Hi Swagger! I know Your post is 8 years old (!) but I'm curious to know if you solved your problem - and how; it is identical to the symptoms I have with copper staining after a commercial grade shock treatment was thrown directly in the pool. Please let me know! My plan is to buy CuLater to remove the copper in the water and prevent future stains, and then buy ascirbic acid powder to remove the existing stains.

The OP of this thread hasn't been on the forum in a long time, so you probably won't get an answer from them. I approved your post and left it here because it can't really stand on its own, but in the future you are generally better off starting a new thread of your own to keep your post from getting lost.

John
 
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