God bless you! All your ideas sounded good, but I already returned the smaller hose and cut the wider hose in half, so I preferred to make it work with the wider hose. I bought a mini hose clamp and I think it did the trick. Is that what you meant? (Not a radiator hose, itself.) I could only feel a slight wetness around the seam after I installed it, but could not see any drips. And I feel like I won't need to worry that the hose will suddenly pop off and drain the pond. Thanks again. I never would have thought of such a simple fix.

I think it sounds right. However, you should probably double check to be sure there is not a slow leak by checking in a couple days. Also, it is wise to raise the pump off of the bottom of the pond so that any future leak from the same or different location would only partially drain the pond.

I checked the connection today and it does have a small but steady drip coming out. The hose seems firmly attached and won't budge when I pull on it. So the drip seems relatively minor. Maybe if there was some kind of tape I could wrap around the inner fitting that would fill any small gaps inside the hose, that could fix it. But otherwise, it's really not bad at all.

try electrical tape, it works well.

Thanks Hal, That's just what I was thinking, but wasn't sure whether that would work. I will leave it alone for now, but will try if the leak starts to really bug me.

I suppose that a small leak, especially if it were located where one wouldn't mind a little water, would be OK. Hal: I am having a hard time seeing how tape would help since either it would wrinkle as the hose was attached, or the unevenness or the point where the tape ends would be a leak area. But I have never tried it. If I were concerned, I would try a different type of hose.