I am in the process of putting in a IG vinyl pool.Just a few questions on different choices. One builder will install a steel wall pool with a concrete bottom and Jandy products pump sand filter and SWG. The other will use a polymer wall with a vermiculite/ portland mix for a base with Pent Air filter system and SWG It will be a 16 x 32 Grecian . On the steel pool the steps would be inside with the liner over them and the other would be a fibreglass step. Here in North Carolina the ground is heavy red clay. Any suggestions on either build ? The prices are very similar. Thanks for your help.