He found nothing/no remains of the nem. I should be home in about an hour to make sure myself, but he's a seasoned reefer so I would think he'd be able to find any remains. I searched for a Mertensii for 2 years and finally found one locally for a great price..that one is going to hurt for a while.So is your mertens gone now? Nothing to pull out?
Beautiful tank, look at it as another opportunity to get some other things you like in the future. Your tank looks aged/healthy otherwise, I would think it would recover pretty fast.