Can you guys help tell me what this is?

[mitch08]

Hey guys,

Im hoping someone here can help me determine what this stain / algae is and give me some advice on how to get rid of it.
At first glance I got nervous because I thought my liner was fading really bad in the low end corner. But after staring at it forever, I dont think its fading... The liner is only at the end of its 2nd season and I dont put bleach anywhere near this area. I put the bleach by the return in the deep end...

It seems to limit itself to just this one area in a corner of the shallow end, but I think I see a bit around the parameter of other areas of the pool.
I know you will probably ask me for my different levels... And all summer I kept them perfect. But since its so cold here now, I dont bother ever testing. I just dump a bottle of bleach in every now and then and run the filter. The water is pretty clear (although far from perfect)... Im closing the pool in 2 weeks. Water temp is in the low 50s.
The annoying part is that I scrubbed and scrubbed this area with a brush and it doesnt seem to be helping at all. So I put about 2 x 1 gallon jugs of 12% bleach in 2 days in a row... Again without taking levels. I know this is blasphemy here, but when the summer is over I get ultra lazy

Pics are below. I know it will be tough to tell from a picture but thanks a million for trying:

 

[dmanb2b]

Of course we're gonna ask you for a full set of test results . It doesn't look like metal staining. To see if it is organic try rubbing the affected area with a trichlor tab.

But before dumping anymore bleach in...please check your levels...it takes just a few minutes and liners are expensive.

 

[chem geek]

To see if it is organic try rubbing the affected area with a trichlor tab.

This is a vinyl liner so I wouldn't use a Trichlor tab on it since the acidity is not good for vinyl. This doesn't look organic. Too bad the water is so cold; otherwise you could feel this with your feet to see if it's rough (possible scale) vs. slimy (possible algae). I'm kind of hoping you've got very hard water and that this is scale since that's easier to take care of, but we need full water test results to see if that's it. If you haven't been testing, the pH may have risen a lot which can lead to scaling and metal staining.

 

[mitch08]

Thanks guys!!! I will do the full test of the water tomorrow and report back. I appreciate the help!

 

[mitch08]

Ok so I have some numbers:

CYA = 35
Free CL = 21
CC = 0
PH = 7.4
Calcium Hardness = 210

7 days ago when I noticed this stuff I put in 2 x 12% 1 gallon bottles of bleach 2 days in a row. So the free cl number makes sense. But Im surprised it hasnt gone down at all in an entire week. Its very cool here and it gets dark out at around 5pm and the water temp is around 48-50 degrees. Does it make sense that the CL wouldnt go down much at all?

Anyway, after a week of sitting with that very high CL I tried brushing the area again. Nothing... It won't budge.
Is there any way this is the liner worn in those areas? I really hope not. It doesnt appear to be but I cant tell. I cant get in there to feel it. The water is SOOOO cold

Thanks a million for your help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[zea3]

Does that area of the pool get a lot of direct sun in the summer? How high do you usually keep your Chlorine in swim season? The liner might not be worn, but it is possible the dye used is not consistent in quality throughout the liner. You might try contacting the liner maker if all other possibilities have been eliminated and see if the warranty covers fading.

Since the water is cold chlorine will last longer that it does when the water is warm. Less organics grow in cold water and there is no swimmer load so less chlorine is consumed. Also less hours of sunlight to burn off chlorine during the day.

 

[mitch08]

I guess it gets a decent amount of direct sunlight. I keep the chlorine around 4-6 most of the summer. Sometimes if a lot of people will be over I bring it up... But I dont normally keep it high at all.

I cant tell if its a dye defect or fading or an actual algae. It just seems to have a color to it that doesnt look like a fade.
I wish I could get in it to tell but it might have to wait till next year.

Assuming it is a defect and I would need to replace it, would I need to swap out the entire liner?

 

[mitch08]

Re: Can you guys help tell me what this is? - Update!

I just noticed that the steps seem to have the exact same discoloring on them. They are the typical white fiber glass steps...
Im pretty sure they have it on them. I reached in (and froze my arm off) and rubbed and rubbed but it wont come off.

Any ideas?

 

[dmanb2b]

Only idea I have at the moment is that if it is metal staining, try holding a vitamin C tab near the area to see if it lifts the stain....other than that I'm at a loss...sorry

 

[Poolschoolgrad]

Looks like staining from Iron.
Is your fill water from a well?
Are your return(s) and skimmer(s) stained?

dmanb2b has the right idea.
Rub ascorbic acid (vitamin C) on a small area of the steps that are stained. If the stain gets lighter then you know it is metal staining.

 

[mitch08]

Thanks. Im going to try the vitamin C this week. Ill report back.
I dont have well water and havent really added any significant amount of water to the pool in a while.

I havent noticed any staining on the skimmers but I havent really looked for it. As soon as I can Ill check that out also.

I really appreciate the help!!!

 

[mitch08]

I used the vitamin C tabs on the steps and the liner (with tongs and I could barely reach with my shoulder all the way into the 49degree water. OUCH )

The stain lightened on the steps and liner almost immediately. I couldnt believe it. If I left the tab for a minute or two the stain disappeared.

So how on Earth do I get rid of it? Can I just leave it for next year? Or can it have a damaging affect on the liner if I leave it too long when I close the pool?

The real question is where on Earth did it come from? My PH is pretty consistant. I havent added a significant amount of water to the pool other than bi-weekly refills from evaporation. It is not well water... If its copper I guess it could be the heat exchange. But from what Im reading it doesnt look like a copper stain (although admittingly I wouldnt know)

Thanks for everyones help. You guys are the best!!!!!!!!!!!!!!

Just a quick edit: Can iron somehow come from leaves? Cause this fall has been windy and Ive been pulling leaves out of the pool like there is no tomorrow.

 

[Poolschoolgrad]

Here is a link to pool school with more info on how to remove and how to prevent these types of stains:

pool-school/metal%20stains

Natural Chemistry makes an ascorbic acid product called Stain Free.
United Chemical makes pool stain treat and super stain treat.

One of the HEDP based sequestrants after treatment will help prevent future staining.

Please send pictures after treatment.

 

[mitch08]

Here is a link to pool school with more info on how to remove and how to prevent these types of stains:

pool-school/metal%20stains

Natural Chemistry makes an ascorbic acid product called Stain Free.
United Chemical makes pool stain treat and super stain treat.

One of the HEDP based sequestrants after treatment will help prevent future staining.

Please send pictures after treatment.

Thanks! I ordered the Natural Chemistry AA. Should be here in the next couple of days.

In the meantime, I couldnt resist, so I hammered down a bunch of Vitamin C tabs into dust and put them into a sock.
I tied a knot in the sock and dropped the sock onto the area that had the most staining (in the first pic above)...
the stain almost immediately dissapeared. Its pretty wild to watch. The only thing that makes me nervous is that the first area I hit with the sock seems very faded now.
Its only a very small area in the corner so Im not too worried about it, but I dont want to be creating a problem.

I also put the sock on other areas after and the stain went away but I had no fading. Is it possible the initial concentration was high enough to instantly fade my liner like that? Or is it more likely it was a just whiter in that area all along and I didnt notice it... I guess what Im asking is, can AA fade out a liner in concentrated amounts? If so that would give me hesitation in dropping in a few pounds of it...

Thanks again for all your help and patience!

 

[Poolschoolgrad]

Mitch

Great to see you found success with your initial Ascorbic Acid tests. If you follow the label instructions, the Stain Free is safe to use on vinyl liners and on fiberglass steps. 1 pound per 10,000 gal of water yields only a concentration of 12 ppm. In fact, it is safer and more user friendly than some other treatments. Follow the instructions carefully from the pool school post and you will not believe your eyes as the stains disappear.

Proper water balance, even in the off-season, is the key to avoiding these types of issues.
A good quality test kit can help you keep your pool chemistry in top condition.
pool-school/pool_test_kit_comparison

 

[mitch08]

A couple of days ago I put in the AA. About 3 pounds. Every bit of staining was gone within 30 minutes to an hour. The liner looks brand new. So thank you very much everyone for your help!!!

Hopefully the filter will remove any metals in the water now. Or Ill deal with it next year. Its like 30 degrees over here and I still havent closed the pool. So Im thinking that is more important

 

[bk406]

Hopefully the filter will remove any metals in the water now.

The filter will not remove much of the metal, if any. The AA reduced the metal so now its just dissolved in the water. You will need to add a regular dose of metal sequesterant to the pool to keep the metal from dropping out and staining the liner again.

 

[Poolschoolgrad]

From Pool school:

ProTeam's Metal Magic and Jack's Magic the Pink Stuff (regular), the Blue Stuff (fresh plaster), and the Purple Stuff (SWG) are some of the top sequestrants. You can also find many other brands with similar products, some of which are noticeably less expensive. Sequestrants based on HEDP, phosphonic acid, or phosphonic acid derivatives are the most effective.

Add a quart of a good sequestering agent after the AA treatment and 6 to 8 oz every month or so. No more stains

Be sure to balance your water after the AA treatment. The PH may be low. You will need to add chlorine also.

 

[chem geek]

If you now have your pool water tested for metals and it shows a measurable result, then you could try an experiment with Culator Metal Remover rather than using a metal sequestrant on an ongoing basis. This isn't a standard recommendation (using a good sequestrant is, as noted in the previous post), but I'm dying for someone with a significant metals problem to try this product to see if it actually works as advertised to physically remove metal from the water. We don't have a lot of options for dealing with metals and a sequestrant really just hides the problem and requires periodic addition.

On the other hand, if your pool is large and you've got a lot of metals, the Culator will be very expensive. I'm kind of hoping your pool isn't too large and you have measurable, but not too high, a metal reading.

 

[Poolschoolgrad]

For a short duration application to treat metals that entered the water from a copper based algaecide, the Culator metal remover treatment could be cost effective. However, for most applications where metals are constantly added from fill water, it would not be cost effective.

$320/ year compared to $42/ year for 2 quarts of Jacks Magic Purple stuff.