Wow! I feel for you. You are getting a lot of great suggestions and recommendations and I hope in the end everything works out! As a rule of thumb for every 100 ft, you experience 44PSI, if your tank height is 3 ft, that chip will experience about 1.3 psi. So a nickel size chip will see approximately 1 lb of of static force. Will that be enough to be of concern? Yes, but It is all relative on what risk you are willing to accept. Another analogy is look at how bottom bulkheads are installed and sealed. It does not take much torque to create good seal. Just my thoughts and I could be way off someone may be able to correct my rough analysis.