Ok - here's some important facts about the Leopard Shark (Triakis semifasciata).
The species maximum length is a about 6 ft long, average is about 5 ft.
They generally take about 7-10 years to mature - and can live for more than 25 years.
Males mature at around 3 ft, females closer to 4 ft.
BTW it's currently illegal to buy/sale or catch a leopard shark under 36" in length.
Also an adult leopard need a tank/pond/lagoon that is at minimum about 9,000-10,000 gallons - not the 4,000-5,000 gallons often quoted by websites or in "Aquarium Sharks & Rays". Basically either a circular pool with a diameter of 18' or an oval pond that is has a length that's 27' with a width that at least 14'.
Note: the length of the pond about 4.5x the maximum length of Leopards, while the width of the pond is equal to about 2.33x the maximum length of Leopards. and these are absolute minimum - any thing smaller is really too small for a 5-6 ft long swimming shark.
As for Water temperatures - so long as it's between 60-75F you should be fine.
Possible tanks mates - Horn Sharks (Heterodontus francisci) & Gray Smoothhounds (Mustelus californicus) are good options, as are the California Stingray (Urobatis halleri) are the best elasmobranches. Also you could pick other fish that are native or similar species that can tolerate water temps in the 60's to low 70's.