I have been using a 100 gallon rubber stock tank for the last year as my degreasing tank which has been working fantastic. . The other day I noticed that I was loosing a lot of water quickly, and ended up burning up my thermostat because the water got too low. I noticed that there was a 5" crack right above the thermostat. I tried to seal it, replaced the thermostat and refilled the tank only to find out that it did not fix the leak. The tank is outside sitting on top of cinder blocks to keep it off of the ground, and has not been turned off during use. I cut an oval piece of pink 3/4" insulation to fit just inside the top of the tank, and then cut out holes to fit my degreasing pails into so the water does not evaporate as fast. Then I just empty the pails and change the water during the process while checking on the water under the pink insulation. My question is #1, Why would the tank crack ? #2 Is there any way to fix it ? Can you put a liner of some sort around the inside of the tank cutting a hole for the heating element to fit through and sealing it . My tank is wired with the water heater element and thermostat that is shown in this forum.