Re: [Ade] Round for water jump
How high is the object?
I've used rounds from 19 to 26 here, and my experience has been that the larger ones have less consistent inflation. If you're going low (or pulling low), I'd personally prefer to have a smaller parachute, for faster, more consistent inflation.
I've used Lopo's of approximately the same vintage (early 80's) with no issues, but I do think the Lopo has a bit worse inflation characteristics (what do you want, after all, it's a vintage round canopy) than some of the other round reserves I've got. The Phantom is pretty good and the K-20 seems to be the best of the bunch.
The modern, BASE specific rounds are noticeably better (faster, cleaner inflation), although some of that may be because they are a bit smaller. The tektite in particular (no longer available new) seems to have extremely consistent inflation--better than any other round I've seen.