So Natural Black River is simple to mix. Empty the 1kg bag of groundbait into a round mixing bucket, fill a 1pint maggot tub with water, pour this onto the groundbait and mix thoroughly, then allow it to rest for 30 minutes, during this time the water will be absorbed into the groundbait. Then for best results; to remove any lumps and create an even consistency, pass the groundbait through a riddle and it is ready to use.