There’s no siphon, the eshops eclipse has a bulkhead and diamond hole saw. The tank is drilled. I had the same concerns, and while drilling it was stressful since it was my first time, it was actually pretty simple.Set up and fish look great. Be careful with that eshopps. I had one flood on me. If the u tube loses siphon for some reason the pump will drain your sump overflowing the main tank. I never figured out what caused mine to lose siphon, i think my kids are some how to blame lol.
If i were to use one again i'd either duct tape it down to the overflow box or use pieces of a acrylic to make a lock