I think a tank has to have a focus on just losing for losing's sake. If Holland had dealt two or three or more guys away and didn't care about the return, that would be a tank. But if he dealt Tatar for what he got. If he then dealt Nyquist for a 1st and 3rd, he dealt Glendening for a 2nd, and he dealt Gator for a 1st and a 2nd... . That's not a tank to me. Yeah, we lose a bunch of production we wouldn't be replacing (at least not immediately) but the return would warrant those moves, especially with where the team is in the standings.
I also don't necessarily include financial problems as a tank. If an owner has fallen on hard times for whatever reason, and can't swallow more losses on his hockey team...well, it's a lousy decision to make but it's understandable. Same if a team has a massive payroll while getting lousy results. There is zero reason to blow a ton of money on something you're not getting a return on.
A few years ago, though, when Buffalo was awful and then realized they might have to be more awful so started dealing guys for almost literally nothing...that's a tank. They weren't dealing players because they couldn't afford to keep them, they weren't dealing players because the returns justified it, they were just dealing players to be an even lousier team.