[Simons]

you need more info regarding WHERE the leak is coming from, it should not be too difficult to determine.

As for equipment, who ever is available may have to test them to see functionality and asses if the water has migrated into any electrical outlets etc.

worst case you get get a large BRUTE or other container and save some of the remaining water, rock, etc and put your aquatic life in there as an emergency and fairly cheap interim solution until you can either repair or replace the tank.