So I'm in the process of building a 4 unit rack (just about done I'll have pics when it's complete), I'm using 30 qt rubbermaid tubs with dimensions of 22.8x16.7x7in. I was planning on using 4 strips of 4" flexwatt 12"'s long to heat one side of the tub (tubs will going into the rack sideways). I'm just concerned it's not going to be enough and if I use 11" then it will be way too much :confused: any help would be appreciated!