Water change reuse?

G'day all,


I've been offered just about everything needed to start up a marine
tank.

Problem is, we have severe water restrictions here, and I like to
reuse the water I take from my tropical tank during weekly water
changes, and put it on my lemon tree.... the tree loves it.

Is there anything I could do with water change water from a marine
setup... or is it a case of tip it down the sink.

Cheers,


Ben.