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