Newbie - Stain removal via ascorbic acid

[herb396]

24 hrs later and no change in water apperance: water is cloudy and satin seems to have come back over 70% of the surface. ...(maybe I should start thinking about going with a black bottom pool)

I could use a little help on what to do next.

[Watermom]

Herb, I asked Ben to take a look at this thread for you.

[PoolDoc]

Sorry, I missed the fact that you'd gotten the testing done.

I rescanned this entire long thread. There's a lot here that doesn't make sense.

For example, your pool's CYA levels did NOT suddenly drop from 70 - 100 ppm to 25 - 35 ppm, unless you dumped over half your water, and refilled. So, we're missing data here.

Did you change pool stores? Test in a different way? Or ??

Regarding the stains, we've got more mysteries. Now that you've established that your pool store can tell the difference between water with no copper, and with 0.2 ppm, we've got an issue. It would seem that your pool water has 0.2 ppm . . . copper is STILL getting into your pool. I suppose that it's possible that copper is leaching from the side walls. But it sounds more like it's accumulating on the walls. But, if you've been using cal hypo, you should have been removing copper on your filter. (What color has your backwash or filter goo been?)

Unfortunately, there's some underlying chemistry here that I don't understand well -- and if anyone else does, they haven't published in a location where I've seen it! Questions like:
How well can various pool wall surfaces 'store' copper?
Will copper in wall surfaces change from soluble (no stain) to insoluble forms and back?

I can only see two possibilities here:

1. You are still adding copper to the pool, somehow. You could test your tap water, this time and see if it has copper. That would be unusual, but a matter for concern if it is true. Potable water that corrodes copper, will also leach lead into the water. It's rare these days for a public utility to run water that will do that, but I suppose it's possible. Or perhaps you're on a private system?

2. Your original dose of copper (still not really explained) was MASSIVE, and you've 'stored' a bunch of copper in the water and in the walls that's showing up again as the sequestrants break down.

At this point, the first thing to do is eliminate possibility #1, and make 100% sure no new copper is entering the pool.

Then, lower the pH, add sequestrant, and drain!

Sorry, to have to say that, but I'm not sure, given the persistence of the copper in your pool, that there's any choice.

When you drain, you'll need to be careful. First, you can only drain if it's a concrete pool. But, you said it's painted, so I assume it's concrete. Second, you can only drain if the ground is dry enough, so the pool won't float out of the ground. If you are from the Nashville area . . . don't drain till it dries up, a lot. Third, you need to be careful where the water goes. Unlike chlorine, copper is a persistent biocide, and will kill fish and other aquatic life. You don't want your drainage to dump into a stream, leading to a fish kill that brings enforcement folk to your doorstep.

Good luck,

Ben

PS. If there's copper IN the walls, there's no guarantee that it will all be gone from the walls when you drain. So, it's possible that when you refill, some of the staining will reappear. Hopefully not, and I have repeatedly seen copper stains lift over time (unlike iron stains). But, just be prepared. If you want to be sure of no stains, you'll have to repaint.

[aylad]

Store bought "bottled water" was tested for copper and produced no reading.

Ben, unless I misunderstand what you were getting at, I'm not sure that you've established that his tap water is copper-free.

Janet

[PoolDoc]

My bad -- he proved that the store was distinguishing copper free water from water with copper. I'll re-edit to correct.

Thanks,

Ben

[herb396]

I have been using the same pool store for our readings. I just ordered a Taylor K-2006 test kit so I can begin to rule out errors in the testing.

Backwash early this morning was very green, like I've never seen before. Most of the green is now off the walls and were left with light staining in the shallow end bottom and the water is very cloudy / milky water.

Since I have well water, I have the water tested frequently by a professional lab. Last testing was done 4 weeks ago, No Copper. Prior to this year we have always had the water running thru a heater, so any previous years reading of copper were attributed to that, the heater was disconnected in early June.

At this point I want to get clear and balanced,,,let the staining fall where it may, and I'll basically start over again once I'm in a clean usable state,,,or next spring (which ever comes first)

[PoolDoc]

Sorry, I really don't have my mind on this. I'm in the middle of three different projects, and flipping between each one. That's not the best way for me to work.

I'd forgotten that you'd been using copper / trichlor tablets; I just saw that again. I assume you've discarded them? (Actually, if you haven't, then put them in the garbage, in a plastic bag, 1 or 2 at a time. Trichlor does't mix well with garbage, and if you put a bunch in at once, bad stuff can happen.)

Also, if you've mentioned before that you've got well water, I'd overlooked that, too.

If you are ready to pack it in for this year, just raise your chlorine and hold it above 5 ppm till you clear up. At CYA = 30, that should do it. You might hold it at 10 ppm, till you get the 'green' gone.

Meanwhile, DO have your well water tested. It's common to have metals in well water, and if you do, you need to know. It's a pain either way, but it's less of a pain if you deal with the metals from the start, instead of after the fact.

Sorry for the confusion. Unfortunately, dealing with metals is rarely straightforward in my experience. Over time, I've always been able to work out a way to deal with metals in each particular pool, but I rarely worked it out on the first pass.

Ben