What is the differences between high range and low range hanna checkers and what is the best levels of nitrate and phosphate in both high range and low range ??
HR Nitrate is better for this hobby and is much easier to use. Nitrate between 5-15ppm is usually a good range. Phosphate ULR or ULR Phosphorus (slightly more accurate) is better as phosphate should be between 0.03-0.1 on average