thanks for the reply .my tank has no trim so will buy some strofoam to be on the safe side

I even put in under tanks with trim once they get over 3 foot long. better safe than sorry. oh and do use styrofoam as it is made of various little beads of foam.. and doesn't compress evenly so you could still get a pressure point. use extruded foam 1/2" either pink or blue. neopreem, rubber ect all works good as long as it is monolithic.. don't use carpet under lay ect..

Steve