Well, I used to have marine and freshwater aquariums.. and i can tell ya that there is a lot of bacteria that grows in that water... bacteria that isn't necessarily harmful but can cause moss and house unwanted organisms.

I personally wouldn't use it indoors.. but outdoors, yes..

when growing indoor you want to keep the area free of unwanted bacteria .. or bacteria in general.
Outdoors is much different.

Cheers,Happy growing.
Bob.