I'm using the Red Sea Nitrate Pro test. I bought it in a kit from BRS that included the phosphate test when they were on sale. Overall I like it. Even though you still have to match colors to get a reading, the color wheel makes it very easy to match. The downside for me is you have to wait like 5 min or so for the solution to sit before you get an accurate reading. I think it takes me about 20 minutes to run Nitrate and Phosphate tests.