HELP!! Alternative for R-0871?

[Terrjam]

I am shocking pool to get rid of algae. I am going through the R-0871 reagent very quickly since I am testing multiple times a day (at least two). I have ordered more but it won't be here for 3 more days. Is there anything else I can do to test my FC? I don't want to have made all this progress on my shocking and then go backwards because I am out of testing reagent.

PLEASSE HELP!

 

[JasonLion]

By using 5 ml of pool water, instead of 10 ml, you can measure FC so that each drop of R-0871 is 1 ppm, which uses half as much reagent, but is a bit less precise.