Repairing acrylic

[jejton]

So while filling my tank to test the plumbing and determine how it needs to be leveled, I discovered a leak in the sump. Well I didnt actually discover the leak but water was leaking from somewhere in the sump into the bottom of the stand. So I shut the valves, siphoned enough water out of the tank, emptied the sump and dried the stand. Now how do I best determine where the leak is and then fix it? Its acrylic and I've never worked with acrylic before.