40lbs of CLC to super shock pool

Chlorinating, maintaining the right chlorine levels,
chlorine problems. Dichlor, trichlor, cal hypo, bleach,
granules, chlorine pucks and chlorine sticks.
rat407
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40lbs of CLC to super shock pool

Postby rat407 » Thu 21 Jun, 2007 21:55

I don't seem to be the only one with no chlorine in my pool week after week. So the pool store did a demand test to the water and said it all looked well and I need to super shock. They told me to put 40lbs of CLC in the pool. I just installed a new Quad 60 filter and I have an in ground 24k gallon pool. The water was a little cloudy and I could see the bottom. It cleared up some but when I went back over the bottom the next day I had white dust like on the bottom of the pool.

So how much damage did I do with the 40lbs of CLC, BioGuard brand?


chem geek
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Postby chem geek » Thu 21 Jun, 2007 22:15

Bioguard Sanitizer CLC WP is 67% Cal-Hypo. If you actually put in 40 pounds of this stuff into your 24,000 gallon pool, then (using 65% Cal-Hypo which is close) that would raise the Free Chlorine (FC) level by about 129 ppm!!! And your pH would go way up as well to around 8.8 (and will come back down as the chlorine gets used up). Did you mean 4 pounds instead of 40?

The only good news is that the high pH lessens the effect of the high chlorine. Assuming you started with pH 7.5 and TA 100 and CYA 30, the disinfecting chlorine level in your pool is equivalent to having about 4.2 ppm FC with no CYA in the pool. Nevertheless, that is rather high and hopefully you didn't damage your pool surface, if it's vinyl, nor your equipment. A short event like this is probably OK, but if you have excess undissolved Cal-Hypo sitting at the bottom of your pool, then if you have a vinyl pool you should vacuum that up right away or at least mix it up so it doesn't sit on the pool surface.

To get your chlorine levels down, just expose the pool to sunlight. A lot will burn off rather quickly. You could also buy and add a chlorine neutralizer, but if the chlorine level drops quickly in the sun then that should be OK. Don't try an test the pH while the chlorine is so high -- the test will be meaningless. As for determining the high chlorine level, that will also be hard unless you have a FAS-DPD chlorine test (such as found in the Taylor K-2006 test kit -- an excellent test kit nearly everyone should have).

Richard
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Postby Buggsw » Thu 21 Jun, 2007 23:31

Pardon me, but I had to giggle at the thought of "it all looks well, BUT you need to throw 40 lbs of shock in your pool" Egad! Somethings not well, if you ask me and it may have been the pool store clerk.
rat407
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Water tested after 40lbs of CLC

Postby rat407 » Fri 22 Jun, 2007 12:10

Saturation Idx: -0.2
TDS: 1300
CYA: 100
Tot. Chlorine: 1
Free Chlorine: 0
pH: 7.2
Tot. Alkalinity: 187
Adj. Total Alk: 157
Tot. Hardness: 191
Copper: 0
Iron: 0
This water sample was taken 36 hours after adding the 40lbs of CLC. I added the CLC at sundown Wed evening. I vacuumed the bottom of the pool last night and then backwashed my DE because it was up to 24psi
This is on a 24k gallon pool inground vinal lined with a new Quad 60 filter and 3/4hp hayward pump.
The pool store is telling me my phosphorous is at 1000ppb and causing my chlorine issue and I have three options.
1. Drain half the pool and refill, if our water supply isn't the phosphorous source
2. Adding another chemical that will cost serious bucks and will have to do it for life unless we exchange water to get the phosphorous in check
3. Something about floc it, they didn't write it down and neither did I.

Suggestions?
chem geek
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Postby chem geek » Fri 22 Jun, 2007 14:26

The pool store is only half right. The main problem you have is a CYA level that is at 100 -- if that's even right since it could be more depending on the test that is used (the turbidimetric test that has the black dot disappear only measures up to 100 ppm).

The cloudiness is from a nascent algae bloom. With the high CYA level, it takes a consistently higher chlorine level to combat it. However, it seems almost inconceivable that something in your pool consumed that much chlorine and that you are now at zero Free Chlorine with 1 ppm of combined chlorine. 1000 ppb is the same as 1 ppm so that amount of phosphorous could not consume over 100 ppm of chlorine no matter what. I am deeply suspicious of either what they claim they are selling you as chlorine or of their water testing.

At any rate, the advice of doing a partial drain and refill is correct for reducing the CYA level and it will also reduce your phosphorous as well. So you might as well do that. And I strongly suggest you get your own test kit, specifically the Taylor K-2006 kit you can get here from Taylor or here from Leslie's or here from poolcenter(dot)com or even your pool store if they carry it (be sure it's the K-2006, NOT the K-2005 -- you want the chlorine test to be of the FAS-DPD type).

Ask your pool store what type of chlorine test they used. If it's DPD that measures the intensity of red color, then it is very likely that the test bleached out with the high chlorine level -- that happens above around 10 ppm FC. If it's OTO that measures the intensity of yellow color, then that does not bleach out but is not usually what is used in pool store measuring equipment. If it's FAS-DPD, then > 25 ppm FC will turn brown, but can be handled by using more powder or diluting the water sample.

Richard
rat407
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Re: Water tested after 40lbs of CLC

Postby rat407 » Mon 25 Jun, 2007 13:14

rat407 wrote:Saturation Idx: -0.2
TDS: 1300
CYA: 100
Tot. Chlorine: 1
Free Chlorine: 0
pH: 7.2
Tot. Alkalinity: 187
Adj. Total Alk: 157
Tot. Hardness: 191
Copper: 0
Iron: 0
This water sample was taken 36 hours after adding the 40lbs of CLC. I added the CLC at sundown Wed evening. I vacuumed the bottom of the pool last night and then backwashed my DE because it was up to 24psi
This is on a 24k gallon pool inground vinal lined with a new Quad 60 filter and 3/4hp hayward pump.
The pool store is telling me my phosphorous is at 1000ppb and causing my chlorine issue and I have three options.
1. Drain half the pool and refill, if our water supply isn't the phosphorous source
2. Adding another chemical that will cost serious bucks and will have to do it for life unless we exchange water to get the phosphorous in check
3. Something about floc it, they didn't write it down and neither did I.

Suggestions?



Saturation Idx: -0.8
TDS: 1400
CYA: 110
Tot. Chlorine: 7
Free Chlorine: 06.6
pH: 6.8
Tot. Alkalinity: 125
Adj. Total Alk: 95
Tot. Hardness: 191
Copper: 0
Iron: 0

Here is the results since I added the 40lbs of CLC to my pool last Wed evening. Since then I have been brushing the pool every day and backwashed the DE filter twice due to 10psi pressure build up each time. I've had three smart sticks in the strainer and just figured to leave them in there until they were gone since they were about the size of a 35mm film container. I've added 3 pounds of CLC on Sat evening and Sunday and then again at 5AM this morning and I pulled the water sample at noon today.
I also had my water supply tested and they said it showed 2Kppb of phospates. Can that be possible?
I can't wait for my test kit to come in so I can check the water myself. I guess to wait to see until then.
chem geek
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Postby chem geek » Tue 26 Jun, 2007 00:18

Though you could have phosphates, the latest "push" from pool stores these days is to treat phosphates with expensive chemicals. Many people have high phosphate pools and don't get algae because they keep their chlorine levels high relative to the CYA level.

By the way, BioGuard Smart Sticks are Trichlor which means that for every 1 ppm FC you add with those sticks, you also add 0.6 ppm CYA and your CYA is already too high so you are just adding to that problem.

Since you have to do a partial drain/refill to get your CYA lower, that will also lower the phosphates and everything else in the water as well (except for whatever the fill water adds -- probably some TA and CH). When you get your own test kit (the Taylor K-2006 or equivalent) you'll be able to test both your pool water and your fill water. Right now, I'd vacuum to waste any junk in your pool and that will dilute your CYA while you're at it (since there's no CYA in the fill water).
rat407
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Location: North Carolina

Postby rat407 » Tue 26 Jun, 2007 20:04

My Taylor K-2006 kit will be here tomorrow according to the UPS tracking. Can't wait to get it and test the water. Especially since we just got over 1.5" of rain and it really filled the pool up.

Thanks for all the help.
lizzy

cloudy pool

Postby lizzy » Fri 29 Jun, 2007 21:38

I need help. I don't know anything about pools. However I pay for the service and my pool is cloudy and has some algae. Also it has white dust in the bottom. Is it safe to swim. My pool service said yes.

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