Flare is back--but I need advice

[xswornxoffxjello]

As some of you may recall, Flare moved into Tiger's side of the tank a few days back. I think this was an accident on his part. Either way, Tiger tore him to shreds () And after spending some quality time alone (and carefully examining the divider--I'm pretty sure that Flare went right over the top and have since lowered the water level) I've decided that it's probably okay to move them back in together. I've been waiting for a time when I could be home to watch, and just put Flare in with some AS. I kind of forgot that I needed to gravel vac. So now, do I put more in? If so, how much? I think they're doing okay right now, but I am really nervous that somehow they'll end up back on the same side. Next time, there will be casualties, I'm sure of it. Can someone please, please help me? Tell me how much AS to add if any, or if they're better off alone than together? Pics of divider attached, water level had been lowered by that point. Thank you.