I am getting ready to winterize my pool here in northeast Ohio...ugh! I have approx. 30,000 gallons of salt water that has been trouble free thus far. My question is how do I calculate the amount of bleach to reach this shock level and more omporatnt how do I measure it my FAS-DPD shows a max of 5-10 cl?

I have read the great clsoing guide, but just cant get behind this one.

In addition, is there a way to get antifreeze down the main drain as I feel uncomfortable trusting the valving to seal water as a head pressure to hold down the water coming back up the return as winter dragssssssssss on here.

The FAS-DPD tests up to 50ppm chlorine (this test uses a powder plus drops). The DPD test which is usually a color block comparitor test (red hues) does only test up to 10ppm but most color blocks top out at 5ppm. The standard DPD is made by Taylor and uses R-0001 and R-0002 reagents to test for FC and TC (and CC).

If you actually do have a FAS-DPD kit, might you be using the OTO (yellow chlorine/red pH) chlorine test? If so, test with the R-0870 DPD powder and R-0871 reagent instead. Then you use R-0003 on the same sample to test for total chlorine. The instructions for this test should be in your kit.

Can you tell us what test kit you're using? Model/maker?

To calculate anything and everything you will ever want to add to your pool, see the amazing pool calculator http://poolcalculator.com

At the bottom you'll see the suggested chlorine section, set the goals to Trouble Free Pool. At the top, enter your pool's volume. In the "now" column put your current test results. The right "target" column is for you to enter the values you want to change to for each section. So, if your current FC is 3, and you want to raise it to 8, enter 8 into the target column and it will tell you how much chlorine to add. You can also change the type of chlorine.

It's very important to enter your "now" value for CYA as that value determines what the calculator shows for your minimum/target and shock level (this shows at the bottom in the suggested chlorine area. As you change the CYA value in the now column, you will see these suggested values also change).

I see....I do not have the kit I thought I have: I have a Leslie DPD http://www.lesliespool.com/Home/Pool-Ch ... 81330.html

It uses the red reagent and hus I can only test fc to 10ppm...viola!

So I think I need another test kit.......i assume the TF100 is the way to fly and will measure these higher levels?

Thanks for the calculator link. As I understand it, the fc is directly proportional to the cya and should never be less than 5% of the cya...is tha correct?

That kit will do just fine, but I would just order the fas-dpd test seprately at tftestkits.net, otherwise it can test everything else the tf-100 can. Once you run out of reagents, then get a fresh TF-100