So I've been wanting to shiny hunt for these guys on my Silver and Gold versions, so I prepared by getting my shiny Gyarados up front (who is still level 30) and buying about 150 super repels on each game, so I can only find the beasts when I go into the grass to search for them and alternating between routes.
I trigger their release into the wild, and I go to search for them... and I never find them. I've used all 150 repels on both games three times (soft resetting) and not a single one of them appear no matter what. Why is this happening? Is there something I'm missing here?