Newbie with a Jonboy Lavatank Question

[Tran imam]

Sorry, but the search function came up with 6000 odd pages in the Lavatank thread. Just bought my first Lavatank, and tried to insert a standard Boge carto from the top and bottom of the tank. It was so tight and once I was able to push the carto through, I noticed that the carto shaved off some of the rubber from the base of the tank. I haven't filled up the tank yet, but suspect that I may have damaged the tank. Any idea where I can buy replacement rubber for the inside of the base (not the o-ring on the outside)? Thanks in advance.