I’m sorry, Hincapiej4, but I don’t have anything to test calcium, magnesium, or alkalinity, so therefore can’t tell you anything. I know that’s a problem. Sorry.
As far as updates on the torches’ status— good and bad. The tentacles are starting to pop out of the skeleton again, but many of the ones that are already out are either deflated, droopy, or half there. Honestly I think it looks bothered by the flow, and hopefully removing excess flow will help. Seeing the old tentacles coming back where I thought they all melted away is reassuring. It looks ticked though, which I am 90% sure is the emerald crab’s fault. I am starting to think Sebastian has to go. I am still concerned about the coral though and won’t be surprised if it dies.
Most of the time, crabs including emeralds eat algae. In a healthy torch, there should be no algae inside the healthy tissue/skeleton, so if a crab is bothering a torch, it's already a worrisome situation.