**Example - Formalin @ 200ppm to a tank 7.5m
diameter and 2m deep** |

Calculate the volume of water in the tank: |

Area = 3.1415 x radius^{2} x depth |

=
3.1415 x (7.5/2)^{2} x 2 |

=
88.35m^{3} |

=
88,350,000 millilitres |

Volume of chemical required = (volume ml / 1000000) x
concentration (ppm or mg/l) |

=
(88,350,000 / 1,000,000) x 200 |

=
17,670 millilitres formalin |

Therefore to dose the tank with 200ppm of formalin requires
17,670 ml (or 17.67 litres) of formalin. |

Note that the above calculation also works for chemicals
dosed by weight as mg/l. 1 ml should be taken as the equivalent of 1 mg. |