Yes, 5 gallons should be enough to cover the 2 tri-clamps toward the bottom, 6 certainly will. I use the 4” kegmenter tri -clamp lid that more beer sells, with the gas post, liquid post and PRV, and a nearly 5 foot floating dip tube with a FLOTit floating dip tube filter. I have 2 other pressure capable fermenters but this one with those accessories and the neoprene jacket produces better beer, even when splitting the same batch between this and any one of my other fermenters.