Mustard alge??

[Watermom]

The PS234 will go much higher. You should have a vial with some powder called R-0870. (Unless the number changed on the new kit, which I don't think it did. It may also be labeled as DPD powder.) You fill one of the collection bottles to the 10 ml mark and then add a scoop of the powder. If that doesn't turn the sample pink, you can add another scoop. Swirl to mix (don't worry if every bit of it doesn't dissolve completely) and then slowly add one drop at a time of R-0871 (FAS-DPD reagent), swirling after each drop. Count the number of drops it takes to turn the sample clear and then multiply the number of drops by 0.5. (Ex. 6 drops x 0.5 = FC reading of 3 ppm.) Then, to test for CC, add 5 drops of R-003 to the sample. If it stays clear, you have no CC. If it turns pink, you again add one drop at a time of R-0871 until it turns clear again and then multiply the number of drops by 0.5. That will be your CC reading. TC = FC + CC. This chlorine test can go way higher than 5. Hope this helps.

EDIT: I'm assuming that the PS234 also comes with the quick OTO chlorine test where you use the testblock that goes to 5. That must be why you thought the kit only went to 5. With the DPD/FAS test described above, you don't use this little test block.