They are now fighting to get their money back after the tanks never arrived.
It has emerged the Queensland Office of Fair Trading received a phone call and written complaint about Aqua Conscious more than three months before a public warning was issued by NSW Fair Trading on January 28.
During that time, the companies continued advertising, attracting buyers across three states.
Leisa Donlan, the chief executive of the Association of Rotational Moulders, the peak body for tank manufacturers, phoned Fair Trading on October 12, but could not progress beyond the call centre despite insisting it was urgent. Ms Donlan then sent a fax the next day warning that Aqua Conscious was taking payment for tanks she believed may not exist.
"We have used our industry resources to establish that this company currently has no contract for supply in place," the letter warns.
But no reply was received.
"It's very disappointing and certainly helps someone doing the wrong thing to go on and create even more damage for players in the industry."
Fair Trading in NSW was the first to act after consumer complaints. Tom Bales of Ebenezer, near Ipswich, paid a deposit on a tank from Aqua Conscious on November 2.
"You would think that would be part of their (Fair Trading's) responsibility to give fair warnings about dubious companies," he said.
Aqua Conscious director Robert Rennie Coventon, from the Gold Coast, told The Sunday Mail last month the deposits would be repaid.
A spokeswoman for the Queensland Office of Fair Trading said the complaint appeared to have gone to the wrong area. It is not clear why the complaint was not passed on to the complaint intake unit and there was no record of it.