I'm thinking about starting to produce some small batchs of biodiesal and have been surfing the sites about it.

One question I can't seem to find an answer for is...

Can biodiesal simply be put in a gas tank that is ...say... already half full with petrodiesal?

Or does the vehicles tank have to be emptied first?

Just dump it in. Normally, they mix fine. Best if both are of high quality and free of water.

Andrew