Roughly 6000 liters(about 1,600 gallons), or basically about 3 meters(9.8ft) in diameter with a depth of 90 cm(35 inches).
It's way too small for requiem sharks.
Even the planned 12,000 liter(nearly 3,200 gallon) pond would be too small for these requiems.
Ideally a Blacktip reef shark should have at least a 6,600 gallon (25,000 liter) pond (18ft in diameter , with a depth of 3.5 ft) to keep it until it reachs maturity (about 3.5 ft). A whitetip reef may be able to stay in a 6,600 gallon pond until it reachs about 4-4.5ft.