Lots of different kits available. Look at the links of suppliers at the first of the Pond Boss website. The most reliable ones that I know of use chemical dyes. Stay away from the swimming pool test strips. Those things put my alkilinity level at 15 to 20 and the pro models say 80 to 90 which is consistent with my area. One recent poster here, don't remember who, said that if you are in pine country you probably need to lime.