Brightwell Aquatics Ferrion 2 Liters. Shake this product well before using. Each ml of Ferrion will increase the concentration of iron (“[Fe3+]”) in 1 US-gallon (3.785 L) of water by 1 ppm. If the initial [Fe3+] in the aquarium is below 0.10 ppm, add this product at the maximum rate of 10 ml per 20 US-gallons daily until the desired concentration is attained, then dose daily or weekly as needed (see below).
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