HELP! Tang Tank EMERGENCY!

Hey everybody,

I need help in a bad way. Last night, half of the water in my 75 gal tang tank spilled onto the floor. The tank is at my g/f's house so I havent had a chance to see it yet. The tank doesnt appear to have cracked, and it looks like the leak may have come from one of the 2 XP3 filters I have on the tank.

Luckily, I have a UGJ that is providing water movement and bio filtration right now. I wont be at the house until later tonight.

First things first. What steps do I need to take when I get there, besides locate the problem? I'm going to slowly refill the volume of the tank to make sure the tank isnt the problem. Are the bio bacteria in my two canisters going to be dead since there hasnt been any water movement in the filters since sometime last night?

How do I salvage this problem? Do I need to worry about an ammonia spike due to possible bio filtration problems?

What steps do I take?

Tank inhabitants:

4 gobies
1 juvie calvus,
12 cyps
3 synos
4 multies

Thanks in advance!!