For reference a bladder could also be a pillow tank but a bladder might or might not be self supporting. The ability of a pillow tank with it's self supporting design and style holds about 70% of what a rectangle would. IPI has labored with tank factories for just about https://www.facebook.com/permalink.php?story_fbid=pfbid02LZsTsj8E3W4hamvhF3Z4Yke9Q5QKc3mSupjP4RU64j2A24H2X1bi3YNymBMXijz9l&id=61560512640678&__cft__[0]=AZVzlK_guTTxxHLEY3950t15YaQLeqfFJyCvMb_uKwH48Z6Zqf1MbrAIVBNvdHiz47nwiTiafIVU23b2YEu933RydFm6EXJZLKd5JM3xYA8EZkKK9_PrID54mYCa1nMl3lFrbdSyvD_PO9Sj0P5WVY23J4S5eH618A-0YN2fI2x9CToytorV2FIQhji9UqspwEXlFne95pX1GPKJbCSltPsP&__tn__=%2CO%2CP-R