Mike, that is what I do. I use my OTO kit daily or at the very least, every other day. Then, I use my K-2006 occasionally. It makes the reagents last a lot longer and for every day use, the OTO/Phenol Red kit gives you all the info you need. If you are fighting something in the water or trying to clear up a pool, you need the FAS-DPD component for testing higher chlorine levels than an OTO can handle but otherwise, the cheaper kit is sufficient for most daily testing. (Plus, replacing the OTO refills are cheap.)