Hello everyone.... im just starting a tank and im running cupramine, anyhow i bought a API test kit to test copper to make sure its at correct level. well directions say i should run it at .50 for about 2 weeks and the test shows a color for .25 .50 1.0 and so on and its kinda hard to tell the color diff between those three. cans someone recommend a cheap and easy to read tester that i can use?