I need a test kit for iron and hardness. Hach seems to be recommended for hardness. They sell some iron and hardness kits, but I don't know what I'm looking at yet. What's the difference between cube and color wheel kits? HA-77 and HA-95A look like good prospects.
It depends on budget as to which would be better, along with what else you will have the need of testing in the future.
The kit with the wheel would let you expand in the future by getting other wheels and test packets while the cube is just that.
I my self like the wheels but they are more than the cube.