I posted here yesterday about the 250 I got off craigs list for 50 bucks I have no experience with large tanks. I have to clean the tank and see where I stand on any work it needs part of the trim is missing but it looks like to me that it did nothing for structural support. Do tanks of this size require the trim to hold it together like the smaller tanks do? I am going to re do the silicone what kind should I use, I have a tube of silicone in the garage I got at the lfs is it all the same? This is going to be a large volume of h2o I cannot afford a mistake at this point. Thanks for any info you guys can provide.