I find empty Turbo shell at the foot of my Gigantea also. Once the snails are within reach it will be pull to the mouth and empty shell spit out. Snails tend to withdraw into their shell when disturbed, or sting, and this is not the way to get away from a carpet.
+1. I find empty shells on the rock below my gig.
Sounds like the zoox population is returning, as evidenced by the darker areas. Make sure the pieces of salmon remain small -- pencil eraser size -- no need for the nem to work harder to digest it. I think it's heading towards a full recovery. Great job.
IME, gigs don't "walk" as much as BTAs or mags. But they do like light, so I'd expect it to keep moving up, though if it's getting enough light and flow it may stay put, especially if it's foot is comfortable. However, since it's bleached, you may end up with an unevenly colored gig -- the top half that's exposed to light will color up first. My suggestion is to remove the top part of the rock structure, so it can climb up to the top and perch upright on the very top. You don't need to help it, just let it do its thing.
Beautiful gig I am in search of one myself. Just got to keep on looking
Very nice... any newer pictures with the coloration to compare to?
Close up pictures of the coloring up area would be nice