Just make sure it's a liquid master kit. Dip strips really are inaccurate--when I was first starting out I learned that when combined with some dechlorinators, these strips can throw false positive results. Imagine how much I freaked out when the ammonia on a tank I had just changed was sky high--lesson learned. They are also extremely expensive per test compared to the liquid kit. For the price of a dozen strips, you get hundreds of tests per bottle of liquid tester.