A lot of people at least Bronze and under need this right now, so thanks for posting!

I'm a big fan of earth splinter against water-magic attacks. I also bring the failed summoner card along. Helps a lot, thanks to the second ability you mentioned (magic reflect).

Event bigger for -1 Water summoner and Djinn Oshannus combo (I laid out this winning battle strategy in one of my recent blogs)

What I missed there was the Death splinter with magic reflect ability. It sure is pretty underrated, (I never tried it myself before writing that blog!)

Good luck, and keep posting!