Hi, we're new caravanners and I was going to buy a 30 litre water porter to supplement our 23litre on board tank. However, as we are planning on using the shower and mainly going on CLs, I'm now thinking the bigger the better and planning on purchasing a 50 litre Water Hog instead. The Water Hog seems much the same as the Aqua Roll (only slightly bigger and less expensive), is there any thing to recommend the Aqua Roll over the Water Hog ?