Perfect Pool Problems???

I have a 13600 gallon pool. I recently had algae and shocked my pool to clean it. Everything read fine and the chlorine levels were perfect. A day later my pool read 0 for Free Chlorine. I have taken my water to be tested and everything reads perfect. I was told to shock it again, so I did and it read to much chlorine. The next day it read no chlorine again. I have changed how long I have run my pump to all day, I have put more chlorine tablets in, I have shocked again and again and the same thing happens after I do that. What could be wrong? Please Help??

Free Chlorine 0
Total Available Chlorine 0
CYA 80
Total Alkalinity 80
pH 7.8

Get a cheap OTO test kit, and test with that.

I'm not sure how you are testing, but if it's with DPD tablets, you may be reading 0 when it's really 15 ppm. OTO isn't especially accurate, but it will give you a reliable indication of what's really there.

Ben

I was testing with a cheap kit and now I have a Taylor K-2005?

What are you using to shock with, meaning ingredients? What kind of pool do you have and what type of filter and size of pump?

The pool is in ground pool, DE Filter, Pentair variable speed pump, Chlor Brite is the product I am using to shock. I started out one week using 2 pounds to shock when I had algae. Then when I saw no chlorine and checked everything and had the water tested fine, they said shock again so I used a pound, then it did the same again so I used another pound.

your CYA is 80, so I would not use the chlorine tablets anymore; most of them I think are trichlor, which will continue to raise your CYA and cause you to have to maintain higher FC levels!
the 2005 kit is DPD, not DPD-FAS, and as Ben stated it can bleach out at higher FC levels- indicating 0 when really 15! The OTO kit will turn orange or brown at higher levels, instead of clear, so will give you
true, if not accurate, indication of FC presence!

madwil's right. You should not use tablets (tri-chlor) or powder (di-chlor) to chlorinate. Stick to bleach/Liquid Chlorine. IF your total hardness or calcium hardness level isn't approaching 400, you can also use Cal-Hypo (calcium hypchlorite) to chlorinate. But always read the ingredients. Names like "Shock" don't mean anything.

You can dilute your OTO kit using the CarlD Shot Glass method (You can search our forum for it) to dilute your pool water. Mix one shot of pool water with one shot of steam distilled water (pretty much every supermarket and discount drug chain stocks it) and test that, and you can double the reading. So if it says "5ppm" it's really 10ppm. Or, use 2 shots of distilled to one of pool and triple the reading. Now "5" means 15ppm.

I THINK you can dilute the DPD the same way--it usually bleaches out at FC=10 or 15...but I don't know for sure. You can try. Meanwhile, a gallon of steam distilled water is cheap and easy to get.

You don't have to go and buy a whole K2006 kit. All you need now is the FAS-DPD portion. That's the Taylor K-1515a kit--just the FAS-DPD test.

You can go to: http://poolsolutions.com/testkit-order-links.html and order the K-1515 via that link. It's through Amazon, but it helps support PoolForum so that we can stay on-line. You can also find this link in PoolDoc's and Watermom's signatures above.

There's also a K-1515C but that just has more of the chems and costs more, otherwise it's the same thing.

Carl

Quote:

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Originally Posted by CarlD

I THINK you can dilute the DPD the same way--it usually bleaches out at FC=10 or 15...but I don't know for sure.

Carl

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You CAN, dilution marks for 1:1 and 4:1 dilutions are molded into the comparator and the instructions for doing so are on the lid in the chlorine test section of the K-2005.

Quote:

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Originally Posted by waterbear

You CAN, dilution marks for 1:1 and 4:1 dilutions are molded into the comparator and the instructions for doing so are on the lid in the chlorine test section of the K-2005.

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Cool! Now I know for sure! I've never used the DPD test in my K2005 equivalent (Leslies re-badge).(I have all kinds of kits around)

Carl