I have a tub with a drain that has no 'closing' mechanism. I guess
what I'd used to call it was a 'trap', the sort of rod assembly that
pushes the plunger up an down and catches all the hair gunk.

So, yesterday, I spent 15 minutes wth a coat hanger and got a ton of
hair out of it, because it was draining a bit slow.

After that, it didnt drain. At all. I've poured a bottle and a half
of liquid plumber, and draino crystals (yeah, I know not good for the
pipes)....

It barely sees to drain at all! So my quesiton is, could there have
been a valve or toggle mechanism I hit while clearing it out to
effectively shut it? Even if there's no knob on the tub or plunger
installed?

thanks

-Mike