A crack in the trim usually doesn't result in a leak, so it would seem that the seal behind has also failed. It will need to be emptied, cleaned, the trim repaired and the tank resealed. How handy are you? It's a bit time consuming, but fairly simple and there are many youtube video's on how to do it. Alternatively perhaps you can find someone to do it?....However, it's as much as a 4 hour job and at say $20/hr. you could almost buy a new tank on sale.
If you are going to repair the tank, make sure you use a glass silicon that is safe for aquariums. The tube of silicon should have a picture of an aquarium on it or should say "safe for aquariums". If it doesn't say safe for aquariums, don't use it.
All you need is a single edge razor blade, denatured or isopropel alcohol, and GE Silicone ! clear 100% silicone. You can pay more for a silicone branded as "aquarium safe", but I've used GE Silicone I, 100% silicone for 20-30 years with success.
Tubes are okay (although I use it in a chalking gun for a more uniform thicker bead) As I mentioned, there are several youtube video's showing you how. Search 'resealing an aquarium'.
In a nutshell, you clean the tank really well first.
First, after cleaning and drying, you need to repair the broken plastic trim. I'd use Max1 German Glue but it's up to you. Super glue or JB Weld.
Then using the razor blade, you carefully remove the sealing silicone being careful NOT to penetrate between the panes of glass. Remove all the old silicone and wipe/clean all the seams well with alcohol. Optionally apply painters tape (I never do) and apply an even bead of silicone. Use a finger to gently press the silicone into the seam. I tend to do the bottom just a bit heavier than the sides. Do the bottom first, then the sides. If you use painters tape, carefully remove before the silicone starts to set.
Be sure to let cure at least 48 hours at room temperature before leak testing.