As for filtration flow rate for shark tanks/ponds/lagoons.
Here's the general guidelines.
While for tanks/ponds under 1,000 gallons - it best to have a turnover rate - that's at least 5-10 times the tank/pond's volume.
Large private Shark lagoon (in the 1,000-10,000 gallon range) tend to have turnover rates of about 3-5 times per hr.
Very large private shark lagoons (in the 10,000-100,000 gallon range) tend to have a turnover rate of about 2-3 times the volume.
Public Aquariums in the 100,000-1,000,000 gallon range tend to have filtration flow rates of about 1-2 times the volume.
And keep in mind that very large Public Aquariums often only have a filtration flow rates of about .75-1 times their actual listed volume per hour. But then these are Aquariums with at least 1 million gallons.