I'm an AF guy and use their products. Just started using NitraPhos Minus in place of -NP Pro because my nutrients were slowly climbing. Use it in conjunction with Pro BioS. Go easy with this stuff because it works quickly. Within 24 hours after 2 doses at 1/2 the recommended amount it lowered my nitrates by 3 points. Do not dose it directly into the tank. Does it into the sump or rear compartment if you have an AOI.