Did you notice that they went from noting-but-dirt to most-tanks-completed in less than 70 days? (In early 2015)
Let's assume they can construct the tanks in 90 days, for one building. And it takes different skilled workers for the foundation, construction of tanks, and the roof. etc.
Then they can do 4 buildings in one year. If they triple the workforce then they can do 12 buildings in one year. Or 18 buildings in 1 1/2 years.
The reason why I'm looking at this is because the latest presentation still says they plan to commission Aquafarm 5 in 2018...