Newbie - Stain removal via ascorbic acid

[herb396]

Test results from pool store as of 10 am today:

Total Chlorine = 1.7
Free Chlorine = 1.7
CYA = 35
PH = 7.2
Total Alkalinity = 95
Adj. Total Alkalinity = 84
Copper = .5

Slight return of stain to steps and small area (10 x 15) in shallow area (near return ports)

[PoolDoc]

Yeah.

Low CYA with full sun will drop your chlorine a lot during the day.

Without a feeder, you probably need to take the CYA on up, so you can start the day with 6 ppm and end with 3 ppm.

Unfortunately, the reappearing stain is probably not really leaving in the first place -- it just changes form, depending on conditions in the pool.

PoolDoc

[herb396]

A week ago my CYA was 100. (where did it go and why?) I only have about 2-3 hrs of full sun.

Should I continue to chlorinate with the cal hypo (I have over 75lbs on hand) or should I return to the BBB method?

The reappearing stain is still dramatically less than when we began. (much more presentable) so were still very grateful to all the guidance.

Thanks

[PoolDoc]

OK, first I need to say the "BBB" method is an approach, not a set of chemicals. (It's my idea, so I get to say what it means! ;) ) Bleach, borax and baking soda just happened to be what's available at the grocery store in generic form. "CHBB" is not as catchy, but if cal hypo were available at the grocery store, that page could have been titled "Cal hypo, borax, and baking soda".

Or, maybe not. My boys used to roll their eyes at me, while griping that I always alliterated at them, accidentally or not, when instructing them in life lessons. :D
-- Lisa, be nice! They really did! Now, they often alliterate, too, driving Susan nuts, since her alliterative achievements are almost always unimpressive. --

Seriously, BBB is not, fundamentally, about bleach. Bleach was just what was available.

Anyhow, your CYA hasn't disappeared. The only way it can do so is if you drain and refill, or if you have bacterial growth (equal major biofilms, AKA seriously slimy sidewalls*) that can biodegrade the CYA into urea and ammonia.

Most likely the difference is a testing discrepancy. Have test strips been used for any of your testing? I'm not sure if they've gotten better, but I know that when I tested several brands of test strips 4 or 5 years ago, the CYA test results were pretty hopeless.


Ben



* See, I just can't stop myself. Now, no doubt, there will be a new acronym: "Yes, you must have had a bad case of SSS over the winter -- that's why your CYA is missing".

[herb396]

My kids roll their eyes at me all the time despite an unexciting vocab,,I just think they become numb to the sound of my voice.

I have a small test kit using drops but limited to pH and CL. Any other test numbers I've posted have always been from testing at the pool store. But after seeing HS kids working at the store, I have had my doubts to the consistency / accuracy.

[aylad]

Any other test numbers I've posted have always been from testing at the pool store. But after seeing HS kids working at the store, I have had my doubts to the consistency / accuracy.

Yep, that's probably where your CYA "went"!

Janet

[herb396]

OK so the plot thickens..The stain has returned in the shallow area,,keeping the CL low (around 2) and adding a bit of polquat...been trying to boost the CL by adding more cal hypo daily (2 - 3 scoops x2 daily) CL has been up to 5 last two days but now the water pool has gotten cloudy and turning green.

Readings as of today from the pool store:
CYA - 28
Tot. CL - 7.5
FC - 6.6
pH - 7.3
Tot. Alk - 110
Adj. Tot. Alk - 102
Copper - .2

[PoolDoc]

Hi Herb;

1. Don't let it go green -- add a bunch more polyquat and a little more chlorine.
2. Check your chlorine again to make sure it has no copper.
3. Have your pool store retest again, BUT, take some bottled water with you and ask them to test that TOO. Say, "I want to see if my drinking water has copper in it." (No lie ;-) If they find copper in that, the copper reading is probably just testing error. If they do NOT find copper in the bottled water, but DO find copper in your pool . . . you probably have copper in the pool and we need to figure out why.

PoolDoc

[herb396]

Ben
1. Done: added both polquat and CL (chloringting granulars)
2. The CL I'm using is labled as 68% Calcium Hypochlorine and 32% other ingredients as provided by "Poolife". I called Arch Chemicals, the company who produces the product, and had them pull the MSDS sheet. They confirmed that there is no copper in this product.
3. Just to be clear: do you mean I should take store bought "bottled water" or should I be bringing them tap water in a bottle as the second water test / along with my pool water.

Thanks,
herb

[herb396]

OK had the water retested at 4:30 pm:
CYA -70
Tot. CL - 7.5
FC - 6.6
pH - 7.5
Tot. Alk - 125
Adj. Tot. Alk - 104
Copper - .2

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

[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