Im in the process of shocking the pool. I bought the test from leslies that was recommended, but it only measures FC up to 5. I had to take in a test sample to Leslie's to determine when I got to FC 16 as recommmended. I want to do the overnight test, however I can't exactly do the test if I can't read the FC that high. Does either of the other recommended test go high enough on the FC to measure FC at the higher levels? I searched and read the info on both tests but couldnt determine if they go that high.