Chlorine test readings

[rollinrock]

I have a IG gunite pool 23000 gals. I cannot seem to ever get my TC and FC to go below 5 or below the top number on the Taylor Test kit. Readings last nite were

FC 5?
TC 5?
Ph 6.9
Toal Alk 130
CYA 50

The reason I quesiton mark the F C and T C is because they are darker colors than the top number on the test kit which I beleive is 5. The TC appears to be a little darker.

I use liquid chlorine and use 3 Leslies chlorine pucks a week in a floater. Water looks great but the Chlorine readings drive me nuts becue I dont kow if I have too much CC or if the water is safe. Does anyone else have trouble comparing the shades of the results to the numbered results on the test kit?

[rollinrock]

How does a lot of people here get Chlorine readings of 10 to 20 ppm when the test only goes up to 5 or 6.

[chrisexv6]

Total Chlorine (TC) = Free Chlorine (FC) + Combined Chlorine (CC). If your TC and FC colors are different, you have some combined chlorine. The only real ways to tell with an OTO test (like you are doing) is to let the chlorine level come down below 5 or possibly dilute the pool water (that you use in the test) with distilled water and then divide the results by the same ratio (i.e. half pool water, half distilled water....take half of the numbers).

The people reporting such high chlorine numbers are using a different form of chlorine test that uses DPD (powder) and another liquid reagent. It was available in the kit from this site but you cant get it anymore from here. There is an alternative website that has a similar kit but the url deceives me right now.

FWIW I have a 22000 gallon IG vinyl pool that gets full sun for most of the day. With my CYA around your level, I use 3/4 gallon of bleach per day (and thats actually a little too much). You might be needlessly putting a lot of chlorine in by using the additional pucks. See if you can get some distilled water and dilute the test to get some better numbers. You can buy a DPD test kit at some pool stores, they are usually the more expensive kits. The kit on the alternate website is probabyl a better deal but youd have to wait for it to arrive.

-Chris

[chem geek]

http://www.tftestkits.com/

[rollinrock]

Thanx for everyone's help.

Great site.