Test strips that just say OK are going to get you in trouble. You really need a good kit. We recommend the Taylor K-2006 or 2006C (same kit, larger bottles). Take a look at the Amazon link in my signature. It will show you the kit. However, we only suggest purchasing it from Amato Industries and their website is down right now. (Other sellers are shipping the K-2005 by mistake and you don't want that one.) So, until the website is up, orders have to be made by phone. Their number is 800-992-6286.