I have the Hanna checker for Alk. I had been using the Salifert test kit. The Hanna may be a bit less labor intensive than the Salifert. The reading that I get have been in line with what the Salifert test kit was showing. I like it, but my wife says I'm a gadget freak. I disagree. I have the Hanna phosphate checker and I'm thinking about getting the calcium checker. I've read some mixed reviews on that one. If you're thinking about purchasing on line, check out Aquarium Specialty's Ebay store. The checkers are a little less expensive and they sometimes have free shipping.