We actually have a nice little chart for this

Grease Trap or Interceptor Drains (No Grease Trap Fitted)
Size grease Trap Daily Dose Amount Drainage Run Daily Dose Amount
Up to 40 litres 100ml a day Up to 15 Metres 150ml a day
50-100 Litres 150ml a day 15 – 50 Metres 170ml a day
100-200 Litres 200ml a day 50 – 75 Metres 200ml a day
200-300 Litres 250ml a day Over 75 Metres 300ml a day
300-500 Litres 300ml a day
Over 500 Litres 350ml a day
Over 1,000 Litres 400ml a day
Over 2,000 Litres 500ml a day