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.
BobBong Reviewed by BobBong on . Using aquarium water Would my aquarium water be good to feed to my special plants? It's a tropical aquarium about 160L big. I have been using it on various plants in my garden and it seems to have a good effect. From a home measuring strip thing: Nitrites: 0 Nitrates: 100 mg/L pH: 7.2 hardness: very hard! off the scale. Rating: 5