Sounds good but..
I aggree w/ Craig but I would try to send some of that hot water though your heat exchanger thus sanitizing that at the same time. Also, if using ioderfer' it will foam alot at hot temps. You may want to do a cold rinse before sani' the fermentor. If you can its also cool to send that (co2 pressure) sani out the tank though the hose and heat-ex.
btw- where does your cooling water go? Try to capture that for the next brew!
Finally, if you do a cost/value comparison, buying a hot liqure tank will easily pay for its self in utility bills (water and energy to heat it)
Operations Director, Tin Roof BC
"Your results may vary"