At sentencing, Judge Allison Sinclair said the recipe for the cleaning product contained fantasy and Walker's mag wheel cleaning was just a front for his drug operation.
She said the chemical company sourced the fantasy from a chemical importing business.
But the company was told that the chemical could only be ordered in 200 litre drums and the minimum order was for four drums.
And when the companies found that butanediol - or fantasy - was a restricted drug and that the paper work had not been completed, Customs became involved.
"The order was stopped before delivery and an investigation followed. From the text [message] exchanges the jury inferred that you had a knowledge of the importation," Judge Sinclair said.
Crown prosecutor Fionnghuala Cuncannon told the court that the 800 litres of fantasy would have a street value of between $1.6 million and $12m.
She said while it was the chemical companies who determined the amount of fantasy to come into the country, Walker knew it had been ordered and wanted to order a "very large amount".
Walker's lawyer Graeme Newell said it was a "relatively unusual fact scenario".
He said while the fantasy importation was clearly of a commercial nature, the money was to be used to feed Walker's drug addiction.
But Mr Newell said Walker had moved away from his old circle of friends and had the support of his wife and mother.
Judge Sinclair agreed that there was no evidence before the court that Walker asked for 800 litres but that the amount was determined by the chemical companies.
She said it was a large amount "and is of a commercial level that cannot be ignored."
Walker was found guilty or pleaded guilty to 23 drugs charges in all, including supplying methamphetamine, ecstasy, fantasy and cannabis.
"Indeed your offending reflects you as being a person better described as a small time street dealer."
She said she hoped Walker would get help for his drug addiction inside prison.
"Good luck for the future," she said.
