What to do first? CYA > 200 ppm

[PoolLizard]

My "shock" (Di-chlor) from Costco says this on the label:

ACTIVE INGREDIENTS:
Sodium dichloro-s-triazinetrione.... 58.2%
OTHER INGREDIENTS.................41.8%
TOTAL INGREDIENTS.................100.0%

How do I know if it's UNdiluted dichlor?

I now have an 8 oz bottle of R-0013 reagent, so I'm going to keep testing the CYA level about every other day while I'm adding the dichlor. I don't want to overshoot the target and have to refill the pool again. Taking it cautiously while still maintaining the FC at 7 - 10 ppm.

Is this stuff a good price? Even at their sale price, it seems a little pricey to me.
http://tinyurl.com/l5fk6mv

[PoolDoc]

It's heavily diluted dichlor -- pure dichlor would be:

Sodium dichloro-s-triazinetrione.... 98% (or higher)
OTHER INGREDIENTS.................2% (or lower)
TOTAL INGREDIENTS.................100.0%

If you look, you'll probably find the "available chlorine %" -- I'm guessing it will be in 25 - 35% range, instead of 55 - 61% as it should be.

Here's what I've been posting for dichlor:

PoolBrand granular dichlor 50lbs @ Sams Club => ~$2.50/lb (Jul 2013 in Chattanooga)
PoolBrand dichlor bagged shock 24lbs @ Sams Club => ~$2.50/lb (Jul 2013 in Chattanooga)

Kem-Tek dichlor 22 lbs @ Amazon => ~$3.60/lb (Jul 2013)
Kem-Tek dichlor 12 lbs @ Amazon => ~$4.00/lb (Jul 2013)
Kem-Tek dichlor 5 lbs @ Amazon => ~$4.50/lb (Jul 2013)
Kem-Tek dichlor 2 lbs @ Amazon => ~$6.50/lb (Jul 2013)

Nava dichlor Chlorinating Shock 1lb @ Amazon => ~$4.99/lb (Jul 2013)

Keep in mind that Amazon products normally ship free; and that in many parts of the country, you will not have to pay sales tax. Shipping + tax can increase the cost from other suppliers by 15 - 40%, so compare delivered cost, not nominal price.

The prices above compare very favorably to 'wholesale' prices. My local SCP (wholesaler) would match the Sams Club price for me if I asked, but I don't, because he'd lose money doing so -- I just buy from Sams, myself.

Pool Water Products is a wholesaler in the S. Florida, perhaps the MOST competitive pool pricing market, with many pool stores selling commercial bleach. PWP's Sept 2013 sales flyer shows per pound prices for dichlor, ranging from $2.65/lb (50#) to $3.40 (12x2# case). As you can see, Sams Club -- selling retail -- is cheaper. Amazon is only slightly more, but if you don't pay shipping or tax for delivery to your location, will be about the same price.

For reference, 1lb of dichlor di-hydrate (55% avail. chlorine) is approximately equivalent to 7/8 gallon of 8.25% household bleach in chlorine content.