Fighting Algae for months

Quote:

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Originally Posted by rkrgk

But I think the math doesn't add up. 4.26 Gal of 6% bleach for 15K Gallons should add it up to ~24 ppm, correct? I think my pool is bigger than I thought. I think my pool could be 25K Gallons (which would make it approx 10ppm). I never got our pool info when we bought our house, I just assumed that it is just 15K.

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PF = 8; 6% bleach contains ~0.5 chlorine gas equiv per gallon, so:

8 x 0.5 x 4.26 = 17 ppm

To calculate a kidney with fair accuracy, you need to following dimensions:

+ Maximum length
+ Minimum width
+ Small circle diameter (a kidney is usually laid out with 2 radius dimension)
+ Large circle diameter
+ Shallow end WATER depth
+ Deep end MAXIMUM water depth
+ Distance from extreme shallow end to break, along the max length axis.
+ Shape of deep end (straight down, bowl, angled hopper)
+ Which end is deep (small circle or large circle)

You can also measure it by adding 4 lbs of dichlor 55% available chlorine . . . AFTER your chlorine demand is gone . . . . and then testing both FC and CYA. But for now, you know your pool has a strong chlorine demand, and you don't know is causing the demand, so you can't estimate how fast you'll lose chlorine. It's entirely possible that you DID add 17 ppm of chlorine to your pool, but that 8 ppm was used up before you could test.

Ben,

Very good info, Thanks a ton! I think I need to get the measurements sometime when I can.

I did the test this morning
FC - 4.0
CC - 2.0

So my Chlorine is working on something still, I think my brushing was not as good as last week and I can see brownish/greenish residues on the walls and the side of the pool when I brushed yesterday. I have the whole weekend ahead of me, so hoping to have a clear pool by the end of it.

You're definitely getting there. Just keep that FC level up and with vigilance you will overcome the algae infestation. Can't say it enough though, keep that FREE CHLORINE level at shock levels as long as you can without letting it dip down toward the minimum CL levels for your pool. I believe your levels would be a shock level of 12 and a minimum of 2.
The longer your FC levels are below the shock level and the lower below that you allow it to go will determine how long/expensive getting rid of the algae will be.

Thanks Jwhouse.
So I added 4.26Gal of bleach again yesterday. I tested before adding the bleach and my FC was 0 (remember I had 4.0 ppm in the morning). CC was 1.0ppm
After adding Bleach and brushing
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FC - 14
CC - 1.5
Tested this morning, I took only at 7:15 am, so sun was up for few minutes, but pool is at the north side of my house
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FC - 9
CC - 1

BTW, is CYA difficult to dissolve. I see mentions in posts about using a sock to put in front of the return?

Keep hammering it with bleach and yes, you can put CYA in a sock in front of a return. If you squeeze the sock occasionally, it will dissolve faster.

Thanks Watermom! I will do that.
And checked the Cl level again (11:30 am) , its depleting very fast in sun.
FC - 3.0 (was 9.0 at 7:30 am)
CC - 1.0

I am not really sure what it is, but I am a bit freaked out about it now..
I was running my hands on the pool walls, and I can feel graininess. Its like when I run my fingers some small grainy/sandy substance comes out. When I look closely I can see white granules coming out of the wall as I run my fingers.
What is it? Is it calcification? or is it that some substance is corroding the walls and what is coming out is part of concrete?
There is also powdery substance at the bottom of the pool and the pool steps and when I brush they just come out and make the pool cloudier.

I would think you would need to check your pH and Calcium hardness. It MIGHT be your plaster eroding. But I don't know.

My pH is 7.3 and CH - 400 (I tested 3 days ago). Can it be the plaster eroding?

Ok, I did some more checking, and seems like there is a layer of white powdery substance on top of the decorative tiles as well (which lines the top edge of the pool walls). It comes off if I scrub bit hard. That makes me think it could be calcification? Can 400ppm of hardness cause calcification?