When Mike goes to see what's in the water his regs are a yellow hose/black reg and a black hose with yellow reg, a battered blue air tank and he is wearing black split fins.
Before he enters the water, he has the yellow hose/black reg on left side. This switches to the right side the first time he surface then back to the left side the second time.
Next is an underwater shot and he has a black reg on a black hose with a red hose protector and blue full fins.
As the shark attacks the CG diver has a completely black air tank.