My sister in law needs help

[Winger 03]

To make a long story short, here is where my sister in law is and I need some help in directing her.

She has an above ground pool with a sand filter and a dome over top of it. She opened as usual and everything seemed to be going ok, but then the pool turned green. She was using pucks or granualr chlorine ..... You know the story.

A couple of weeks ago, I turned her on to this site to get straightened out. She ordered the TF-100 from Dave, and got started. I was out of town last week so she and I did not speak until this am, and I am concerned the something is not quite right.

I am having her run a full set of tests and will post them here as soon as I get them.

Where she is right now is that she poured a gallon of MA into the pool to get the pH in line and about 8 gallons of bleach. All of this was according other according to the pool calculator. None of this is really too out of line for a green pool, but then we spoke this am, and our conversation prompted this post.

She tells me that her FC is in the 200 range (she stopped at about 400 drops and the sample was mostly clear). I walked her through the test procedure and as I described each step, she said that is how she was doing it.

Something just does not add up, and the pool is still green.

My initial thoughts are......

Incorrect testing
CYA way off the charts
Something else

I'll post a full set of results and pool specs shortly, but prior to that any reason why the FC test is incorrect?

 

[JasonLion]

The FAS-DPD test can go wrong in a couple of different ways. If you add drops way too slowly the sample will turn pink more or less permanently, resulting in what appears to be infinite levels. Another possibility is that the pink went away a long time ago and now she is waiting for some other color/tint/cloudiness that came from the pool and not the test to go away.

 

[Winger 03]

OK, now we have some numbers ......

pH 7.5
Fc 16.5
Cc 3.0
TA 140
CH 320
CYA 40

So she is now just barely at shock level, so I told her to retest in about an hour and maintain 16.

Poolsize is 13k gallons, vinyl liner.

Thinking something was up from some of her initial problems, I asked her to run to the pool store and get a test done there. The store said all numbers were ok (thought they did not give her a printout - take it for what it is worth). They did mention that copper was present and high, though again, no numbers were given. They suggested a sequestering agent though before going I told her not to buy anything, just get the water tested.

That might explain the green tint, but with a Cc of 3, there is still algae in the water which is most likely why the water is not clear.

I suspect I am telling her the proper things to do, but if I am not, please let me know.

 

[JasonLion]

You are doing fine.

If there really is copper in the water it will turn the water bright transparent emerald green while shocking. But the CC level wouldn't come from metals and is presumably algae as you said.

 

[Winger 03]

Thanks Jason. I still think something was up with her initial Fc testing and perhaps the culprit was going too slow as you suggested. I'll tell her to remain vigilant with the testing and dosing.

It seems from reading threads here that this part of fixing a pool is the toughest especially since those in trouble got there by not doing much at all except adding too much stabilized chlorine. Now we are asking them to test every hour and dose with bleach as needed. Too much work! ;o)