Discrepency btw store's H20 test and PS233

Checked my pool today using quick PS200 kit and got alarmingly HIGH chlorine results:

TC= Dark Orange (beyond readable)
pH= 6.8

I purchased new hth chemicals for this quick kit from Wal-Mart this past June 2010. Shocked to see such a high cl level, I decided to 'pull out the big guns' and use my DPD test. {My titrating reagent and powder are a couple years old}...My result was:

FC= 37!!! Yep, I used 74 drops b4 the pink color disappeared in the water sample

CYA= 90 when I opened the pool in May. (I'm out of the reagent to re-test it at the time of this post... But, I have been keeping my cl level high approx 8 due to the high CYA)

I typically add approx a cup of powdered chlorine a day or 2c every other day...{Gave up on liquid bleach-too many suits/tee's bleached out}..Water has looked beautiful...Clear, blue, etc, since opening 2 months ago..

Anyone ever experienced such varying test results? No one's been complaining of red eyes, rashes, etc. I HAVE noticed my daughter's hair has a green-ish tint. I was going to add some Metal-out soon....

Here are *my* readings in full:

TC= Off the charts orange
FC= 37
pH= 6.8
TA=50
CYA= 90 (taken May 2010)

Here are the store's readings in full:

TC= 1
FC= 3
pH= 6.8
TA= 80

My pool is a 28ft round above ground with an 8ft deep end = approx 26,000 gallons..Sand filter, vinyl liner. Any advice would be greatly appreciated....

I should add that I've used both the quick testkit PS200 chemicals and the PS233 kit all summer with what I thought were normal readings. This result today was the first of its kind....

One thing that strikes me off the bat is your pH--your kit measures 6.8, but because that's the lowest it will test, it actually may be much lower. Anything lower than 7.0 is acidic and can damage your liner. Also, chlorine that high usually gives falsely high pH readings, so it probably is lower than 6.8. You need to get some borax in the pool ASAP and get the pH up over 7.0.

I would absolutely trust your test results over the pool store. Chances are good that the chlorine being so high just bleached out their result--but if you're using drop testing with powder that is light grey or lighter, then I would absolutely trust your result. The chlorine will come down on its own--but you do need to address the pH quickly.

Janet