It is not algae... and vitamin C did nothing. These marks are a mystery, let's solve.

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FixItPete

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Apr 7, 2012
152
I'm at the end of my rope.

I have these "brownish" (slightly red... but really brown/black) streaks in my pool. Mostly in the shallower area and also on the radius where the wall meets the floor.

I have maintained a consistent 30PPM... they don't go away. I have used different algaecides (I know, TFT hates them)... I have tried everything. I tried the "eraser" (rubberized attachment for my pool pole) and that has little, but not a great effect. I tried placing a "puck" on top of a stain - nothing. I tried the vitamin-C - nothing.

The pool is normally kept spot-on at 4PPM, with proper PH, etc...

What's the deal? Any other tricks? CYA is at 35PPM... everything else is as it should be. I've brushed while maintaining a long-term 30PPM...

The pool is maintained with a Stenner, and acid is added weekly to spec.
 
Have you used copper based algaecides? If so, they could be copper stains which cannot be removed by ascorbic acid (vitamin C). Copper stains require a more complex chemical removal process and, if there’s too much copper in the water, you will need to dissolve the stains and drain the pool. Jacks Magic sells a stain ID kit that can differentiate copper from other more common metals.
 
LOL. No, it is normally at ~ 3PPM. It was only being maintained at 30ppm to see if this staining could be dealt with. My OP explains that. :)

I have used Yellow-Gone in the past with success, but not in a very long time. I did try it again to deal with this issue, to no avail. This issue was here before the second time using Yellow-Gone, so not a copper issue. (I'm not even sure if Yellow-Gone is copper based).

Here's a picture... you can see the "streaks". I can tell you that I just went out with the "eraser" and it doesn't come out.

pool.jpg
 
If it’s the stuff from HomeDepot then it’s EDTA which just creates a lot of CCs when added to chlorinated water. Won’t hurt anything but will raise CCs when using it.

Can you post a full set of water test results including CH and, if possible, your fill water TA and CH?

Do the areas feel rough and raised?
 
JoyfulNoise said:
If it’s the stuff from HomeDepot then it’s EDTA which just creates a lot of CCs when added to chlorinated water. Won’t hurt anything but will raise CCs when using it.

Can you post a full set of water test results including CH and, if possible, your fill water TA and CH?

Do the areas feel rough and raised?
Click to expand...

The areas do not feel rough and/or raised. Just stained.

I can post all the stats if you would like, however, they are all within the range within the Taylor test-kit (K2006) book. (except for right now on account of the high FC 30PPM (which I am currently letting slide downward toward maint. level.)...

If you're asking about fill water... as in water from the hose that is used to fill when the level drops, I can do that at some point.

Hopefully somebody that sees that picture might have an idea...
 
TFP doesn’t follow the recommendations from the Taylor book as those are industry standards which tend to be sub-optimal values.

I am asking for your most recent test results because I’d like to know what your CSI (saturation index) is. If your water has a positive scaling potential and if it has been that way for a long time then it is possible that what your seeing is essential dirt + calcium scale which would not respond to either chlorine or vitamin C. If your saturation index has been negative for a long time, you could be seeing plaster etching which can sometimes reveal the defects in the plaster or cause a blotchy appearance.

You can also try to see if wet sanding a test area works. You’d need to get a 280 grit or higher (finer grit has higher numbers) piece of sanding block or paper and rub the area with it. If the wet sanding improves the color and uniformity, then it’s a physical surface defect and you don’t have many easy options.

You’re in Florida so I don’t expect your water to be hard (high in calcium) but it could have detectable levels of iron in it especially if it is well water. That iron can combine with scale over time and cause the scale to look brownish colored. Vitamin C would not necessarily lighten the scale color.
 
JoyfulNoise said:
TFP doesn’t follow the recommendations from the Taylor book as those are industry standards which tend to be sub-optimal values.

I am asking for your most recent test results because I’d like to know what your CSI (saturation index) is. If your water has a positive scaling potential and if it has been that way for a long time then it is possible that what your seeing is essential dirt + calcium scale which would not respond to either chlorine or vitamin C. If your saturation index has been negative for a long time, you could be seeing plaster etching which can sometimes reveal the defects in the plaster or cause a blotchy appearance.

You can also try to see if wet sanding a test area works. You’d need to get a 280 grit or higher (finer grit has higher numbers) piece of sanding block or paper and rub the area with it. If the wet sanding improves the color and uniformity, then it’s a physical surface defect and you don’t have many easy options.

You’re in Florida so I don’t expect your water to be hard (high in calcium) but it could have detectable levels of iron in it especially if it is well water. That iron can combine with scale over time and cause the scale to look brownish colored. Vitamin C would not necessarily lighten the scale color.
Click to expand...


Thanks... it is not well water (regular city water).

I can tell you that rubbing with sand paper will not remove it (the "eraser) that I am using is essentially sandpaper embedded in rubber...
The Stain Eraser for Concrete Pools, Beige - Doheny's Pool Supplies Fast

It is some kind of staining that clearly very hard to remove... I'll get you exact number for all the tests in the K2006. However, nothing is going to jump out as off-the-charts...
 
I just replied with the other user id... but it didn't post... I'll try again, right now...

Edit: There you go.

Now we got the dual ID issue resolved... can we move back to figuring out what those marks are?
 

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Based on your picture (and my own experience with similar issues), it sure looks like copper staining to me. That could happen from using algaecides. I had to learn that lesson the hard way, many years ago, before I found this site. I would definitely get the Jack's Magic Stain ID kit to rule it out. Best of luck!
 
Pete, thanks for correcting the user id issue. :goodjob: After reading this thread, I am intrigued by what I see and some of the history details such as:
- You mention using Yellow Gone on a couple occasions, but also note in post #1 of using "different Algaecides". Perhaps some other brands are contributing to the marks?
- It may not happen in all copper cases, but there are times when an owner places vitamin C on a stain they think is iron and it gets worse (copper). But yours didn't do it. That's interesting as well. Do you have any dry acid laying around? If you're able at some point, you might try to get your hands on a small amount just to put in a sock and briefly hold against an area to see if the marks change.
- Your K-2006 test results might still give us a clue as to what could be happening. Curious to see those when you can post them.
- Not sure if you mentioned it elsewhere ... but any idea how old your pool (specifically plaster) is?

Hopefully with some back & forth dialog we can keep moving forwards towards a good idea of what's happening in that pool of yours.
 
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