My new plaster pool is COVERED in green stain..

This is very scary. New white plaster pool. Pool filled with 1/4 of our wellwater (Texas Hill Country) and two truckloads of water from local water company. Pool is about 3 weeks now. I will give all details even though they may not have anything to do with how this happened:

Purchased new chlorine tabs at Home Depot: they were different from what our pool company had given us (blue specks imbeded in them...a filler) thought this might be the problem so took these back and got 100% pure chlorine tabs.

Realized that chlorine was set at full blast on equipment dial (pool tech must have forgotten to tell us to turn it down) so lots of chlorine.

We've had to add meriatic acid a few times...at his advice as we are trying to get water levels to settle down.

Daughter had sleepover and many girls playing in pool over this weekend.

Sunday, pool started getting covered in what appears to be a dark green stain. Does not rub off AT ALL.

Stains are on bottom two stairs..bottom of pool (not as dark in shaded end but still there) seems to be about 6 inches from surface of pool and all over bottom.

Can actually see where one of the girls sat in the spa and on a step...this is puzzling.

I did read a post on metals in pool water and crushed vitamin C in a sock. IT WORKED ON THE STAIN WITH LOTS OF RUBBING.

I got this "metal out" product from pool store and according to directions for my size pool, (14000) etc added that to the pool last night.

This morning still the same.

My fear: could the gunnite be showing through or could this be a plaster problem? So scary when one has invested in an expensive pool and now it is not as it should be. The installer of the pool is very baffled. He has been installing pools out in these parts for over 10 years (well water) and has never seen this. Even he is very concerned. HELP!

Chrlorine is too high to have water tested yet. Waiting for it to go down.

Dark green (greenish blue can be copper) is not a color I've seen, so I can only offer general advice.

1. Try to get your chlorine down -- if it's the pool tech's fault, ask him to lower it. High chlorine generally increases metal staining.
2. Don't bother with liquid metal control agents till the chlorine is down -- chlorine destroys them.
3. Ascorbic acid (vitamin C) is ALSO destroyed by chlorine.
4. Lower your pH as low as your plaster guy allows -- metal staining decreases as pH decreases.
5. Have your water tested for copper.
6. Find some other place to test, if you can -- a pool store that can't test for high chlorine probably can't test anything reliably.

You probably want to lower chlorine and pH ASAP. Stains tend to become harder to remove the longer they are in place. So, it may be pretty urgent to get chlorine and pH down NOW. A responsible pool tech should be willing to make extra trips to resolve a problem he helped create, even if it was an accident on his part.

Also, use polyquat as soon as you get your chlorine low. (High chlorine ALSO destroys polyquat!) And, then, keep your chlorine low, replacing chlorine with polyquat. I'd avoid non-family use for now.

Ben
"PoolDoc"

THANK YOU. I will do this and see what happens.

Do you know what the name of those other tabs were? Did you read the ingredient label? Some trichlor pucks have copper in them. You NEVER want to buy those. I *think* they may be called dual acting or something like that.

Quote:

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Originally Posted by hausfrau

I did read a post on metals in pool water and crushed vitamin C in a sock. IT WORKED ON THE STAIN WITH LOTS OF RUBBING.

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This is setting off warning bells for me. Vitamin C (ascorbic acid) works on metal stains by chemical action (reduction) and does not need rubbing!
Algae often needs a lot of rubbing to remove it.
Metal stains don't rub off unless you rub hard enough to removed plaster.

The other red flag is that the problem started after your daughter's sleep over, which very likely created a low chlorine condition in your pool! You also stated that the stains are not as dark in shaded areas of the pool. Algae needs sunlight, metal stains don't.

I suspect you are seeing green algae on fresh plaster.

Try holding a chlorine tablet on a stained area for about 10 minutes and report what happens. (wear rubber gloves or use something to hold it on the stain) If the stain lightens and/or disappears it is algae.

Please pose a full set of test results ASAP.
Chlorine too high to be tested and chlorine high enough to kill algae are sometimes not the same. It depends on some of your other readings and how you are testing the chlorine. With some water testing setups (even professional ones) chlorine that is too high to test can be chlorine over 3ppm, which is not very high at all and often not high enough to stop an algae outbreak .

Good points, Waterbear.

PoolDoc

Quote:

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Originally Posted by PoolDoc

Good points, Waterbear.

PoolDoc

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thanks! :)

You are all so very helpful. Update: My husband drained down the spa and squired a solution of meriatic acid (10%) and water. Boom. Stain completely gone. A neighbor was able to gingerly rub at a dark smear on the side of the pool and he actually was able to remove the stain. This was using a stainless brush which I am not a fan of and have not used. So, this being said, my local pool store suggested we brush the pool (used nylon brush) and put in a solution called Supercide (algea destroyer and stain remover). Honestly, I don't see much difference. Algea may look a little lighter in some areas. Sometimes your eyes play tricks.

Here's the readout. 14000 gallon pool. temp 85 degrees, algecide level 0, Protector 28 N, total solids 1700, saturation index -0.4, free chlorine 8.0, total chlorine 8.0, alkalinity 45, calcium hardness 220, ph 7.4, stabilizer 100. They suggested low alkalinity and had me buy equalizer. Then, muriatic acid. This was tested on Friday of last week. it is now Monday. I will probably get it tested again tonight as I will be near the pool store.

The chlorine test I am using is a home strip that you dip into the water. I don't like it alot as the reading won't tell you how high the chlorine is...just that it is too high! it will be high right now because of last nights Supercide treatment...I turned off the chlorinator until it seems to level off.

Initially, our pool installer had the chlorine cranked all the way and I did not realize I was supposed to turn it down after a few days. Now that I know how to adjust the chlorine flow, I can better adjust that. Man, this is a pain. I never should have put in a pool ;0

You have algae, and the only way to get rid of it is by using high levels of chlorine until the chlorine holds within 1ppm overnight. With a cya of 100 you need a minimum of 8ppms, and to take the pool up to shock levels you will have to take your chlorine level up to 25ppms and keep it there testing every couple of hours to get it back up to 25. You may also want to do a partial drain and refill to get your cya between 30 and 50. You are wasting money on all the chemicals the pool store is selling you to kill algae that will die with high levels of plain old bleach ;). I would be very leery of the chlorine tabs with specs in them. Make sure they don't contain copper. You also don't want to use the chlorine tabs that are trichlor as they will raise your cya even more. You should take a look at the chlorine forums and the algae forums - you will see that good old fashioned bleach really does work. The best suggestion I have for you is to get a good test kit so you can test your own water and learn how to take care of your pool yourself and not be at the mercy of pool stores. Do a lot of reading on this site, and ask any questions you have. Everyone here loves to help:)