Hello
I've been growing for a little less than a year and the only fertilizer that I use is green nasty water that backwashes out of my koi pond filter. I've been doing this with my fruit trees for 15 years or more, so I figured I'd try it w/ my indoor plants. The plants are great!!!!! They have the sweetest taste and aroma. When I am done trimming them, my hands are so sticky, I feel like I have superglue on my fingertips.
I feed my fish basic koi food, and occasional greens, and I'm sure they eat a bunch of bugs. The sludge I get out of the filter, at cleaning time, is so rich in nutrients, that they really don't need anything else. I don't even flush at the time of harvest anymore because the buds are so sweet and tasty just the way they are. I hope this helps.
One more note, if I've treated the water with potassium permanganate or anything else, I backwash the filter for a week, just out in the yard, before I start using it again. I figure the water is too clean and sterile at that point so why bother. The chemicals you would use in your tank would dissapate or be inactivated by a day or two. Good luck. RECYCLING at it's best!!