Koi Care Kennel ProForm-Cis the preeminent broad spectrum malachite green & formalin treatment. It is formulated differently than any other malachite green & formalin mix. Malachite green and formalin are two drugs that are more effective in combination than if used individually. This is the definition of synergism. These two drugs are also less toxic in combination than if used individually, What makes ProForm-C the preeminent product in this field is the fact it is formulated with malachite green chloride, while all other MG&F products use the oxalate salt form which is more toxic than the chloride form. As with any malachite green & formalin treatment do NOT use with salt levels above 0.05%.