Sanjay, do you know a guy named Brian McNamee or a business called BALCO. I am sorry I am kidding. I wanted to make the HGH joke but House beat me to it.
Dude happy aniversary and just wow, amazing tank. Looks awesome. Keep up the great job.
They are the Eco Tech Vortech pumps. The drive system is outside the tank, and magnetically coupled to the propeller inside through the glass. They move a lot of water, use low electricity, and take up little space in the tank.
Here are some of the non acroporid corals that I have in my tank. As you can see I am expanding this collection more than the acros. Any dead acros are being replaced by some of these really beautiful corals.