For reference a bladder may be a pillow tank but a bladder may or may not be self supporting. The ability of a pillow tank with It truly is self supporting layout holds about 70% of what a rectangle would. IPI has labored with tank factories for just about 2 https://www.facebook.com/permalink.php?story_fbid=pfbid0jkMh3zZpdaBFVGVCXtkebUZHAXhoukeNN1tQbRTiJgC6ncj5rszg5P4JXAKvp2D9l&id=61560512640678&__cft__[0]=AZVLrwd-0v3pYlX6maU8Xnbyiz2uHhcykIxOgHaHbW5APT4wAYAhlP7_57c2mQZeMr3v59cs9QoYuvCu-FnvtACvvrFXyF2O8fHy9er6tjqAeOPsIv4Gg_fLbIb9NBiPzBsAQYqgvqKYbwqpyfZh1s7ShrwUlzz-oOgMVd2rNXNV0f5yMTtDIx7D6M20pj9lRHWeP_9QDYsdbYeaWFYQ-OWE&__tn__=%2CO%2CP-R