Please consider using the specified pipe size

Often fountain spouts are the last item specified on a project. During construction the required pipe sizes aren't always known. The installer must guess what pipe size to use for the spouts. This can lead to problems later on if the pipe is sized too small.

In general the larger sized spouts are not affected as much with changes in pipe size as the smaller ones are. The Large Karlo, for example, works fairly well with plumbing down to ½ in. when the water flow is under 3 GPM. At larger flow rates it doesn't work as well. All in all, that's pretty good.

Big Karlo spout with 1¼ inch plumbing
Big Karlo spout with 1¼ inch plumbing: this is the specified size
Big Karlo spout with 1 inch plumbing
Big Karlo spout with 1 inch plumbing: there is no noticeable difference at 3 GPM from the 1¼ plumbing
Big Karlo spout with 1¼ inch plumbing
Big Karlo spout with ¾ inch plumbing: just beginning to see a difference - the center of the ribbon is thicker than the sides, but the overall effect isn't that much different
Big Karlo spout with 1 inch plumbing
Big Karlo spout with ½ inch plumbing: there is a noticeable difference here - the flow is wider and projects considerable farther than the other configurations. The overall effect is still very nice.

The smaller spouts may not behave so well