Lifestudent;526730 wrote: Hanna Instruments makes handheld colorimeters for $50 and is coming out with more. Click http://reefbuilders.com/2010/06/08/hanna-instruments-checker-colorimeters-alkalinity-calcium-and-nitrate/">here</a> [/B]to learn about them.[/QUOTE]
Have you used these? I'm red-green colorblind and would love to be able to read the tests myself.