Review on Nutrafin Iron 0.0-1.0 mg/L Test Kit for Freshwater and Saltwater - 50 Tests by Michelle Moore

The chelated iron test works well in the lower range, but sometimes I get a color that is 0.25 inch *tint* if you move the tube half an inch from stick to a white background, but the intensity is too bright for the "credulous" 0.25 that I see often. However, if you hold the tube flat relative to the chart (as stated), it will match *nothing* in hue. I really need to know if it's 0.5 or 1.0 as higher levels will require a water change.