Would the 4 inch heat tape be a good size for a 28 quart tub? The tub is 23 inches long so 4 inches would only cover a little less than 1/6 of the floor space. I'm thinking the 11 inch heat tape would be too big though, since it would cover almost 1/2 of the floor space. Just checking to make sure the 4" will be enough. Thanks!