The strips are less accurate than the liquid tests but they work fine. The API 5 in 1 does not have ammonia so you will also need to buy ammonia test strips. You also only are getting 25 tests with the strips so factor that into your cost equation as well. On the other hand, the test strips test kh
which the liquid test kit from api doesn't include and needs to be purchased separately.
The liquid kits require a slightly higher initial investment but have a lower per test cost.