On Thu, 11 Apr 2013 23:48:05 -0700 Oren wrote:

Oh, flush that bleach out. I recall bleach is bad in the tanks as it
can damage parts like rubber.

Interestingly, the weak 4% household bleach didn't do anything
visible when poured directly into the bowl initially ... but ...
afterward, in the tank, the 3x stronger 12% pool bleach DID whiten
the remaining strands of brown stain!

http://www5.picturepush.com/photo/a/...g/12671343.jpg

However, it might be that the pool acid somehow 'weakened' the
brown stain, such that the pool chlorine could attack it - or -
it could simply be that the pool chlorine was stronger than the
household bleach initially used.