01 Looking for the leak

Back story: I began flying again after the tri-gear conversion last spring. At first I noticed that fuel usage seemed excessive. Then fuel started disappearing while the aircraft was on the ground. But there was no sign of leakage. No fuel or blue stains, etc. Upon a return from a short X/C I had to switch to reserve on final and it required 18 gal to fill the tank. Way too much fuel burn for less than 3 hrs of flight. The fuel totalizer said only 12 gal used. Still no sign of leakage anywhere on the aircraft. About a week later I had departed for AirVenture early in the morning. About an hour north, I noticed that the sight gage was showing an astounding fuel use and did not agree with the totalizer at all. I turned around and headed for home. Upon landing I went to the pump and it took almost 18 gal to fill up. I taxied back to the hanger to put the aircraft away, unload and drive to KOSH. When I pushed the a/c into the hanger it rolls over a threshold bump that the door closes over. Upon the bump, fuel begins to flow out of the belly inspection opening. I get my gas cans and giant funnel and collect it. I also take the cowl off, disconnect the fuel line to the engine and use the electric pump to pump fuel out of the tank and into gas cans. Now it is obvious there is a leak in the tank and I'm driving to KOSH. I contact Europa and order a new tank.