it might work for you,
but they actually make something that is supposed to be for de limeing water heaters. if you got the time and patience to use it...
will look around and see if I can find the name of it.
the downside to delimeing your water heater is if it is an older unit,
sometimes the lime has actually worked as a plug to seal up any tiny
leaks that might be starting... so it you clean it out, you risk it leaking someday....
ya cant win