You see I bought this new 100 gallon tank for 100$ but it has this crack on the side wall. It doesn't leak or has any problems because I saw the tank with full water and fish inside. He said he previous owner didn't have a big deal with it nor did he. I want to be more on the cautious side, is there anything i can use to fill up the crack or at least seal it because i fear as my fish get bigger they will ram the sidewall and make matters worse.