Hi there,
I have a new 400l flexitank pro (in the box for a few months in the basement) that is leaking. 
Setup seemed fine but once I filled it and let it sit overnight I found about a cup or two of water around the base. 
Best I can tell the leak must be where the black rim on the bottom meets the flexible wall. The water is pooling from underneath the tank. There is a small section opposite the drain where it looks to be away from the wall very slightly. 
How would I go about repairing that, and how secure would it be if I did? 
Cheers, Tony