Urine isn't sterile, that's a fallacy, it has some bacteria from inside your body in it and picks up bacteria off your skin as it leaves your body. It's not that it's absolutely dangerous to use as fertilizer, it's just a higher likelihood of transmitting human pathogens if it isn't composted correctly to kill everything. In reality, you could use your own, composted, shit also if you wanted. It's not commonly done because of the risk. I believe I read the urine lie was started by the military during ww1 so soldiers wouldn't care, so much, about pissing on a wound to field clean it. If you're dead set on using it, add it to a compost pile and let it break down first. With the amount of animal byproduct available, i don't see the point. Try stopping in at smaller local farms with livestock, sometimes they have an excess of manure they'll let you shovel for free, or offer some labor in trade.
I just started having my roommate save his saltwater tank waste from his protein skimmer. Looks like I'll have about 6-12ozs of sludge ill be adding to 50+gallons of recycled soil every cycle. I might have him save his filter waste, idk. Everything I've read says it's a great source of micro nutrients. I even read that ocean water, diluted at a 10:1 ratio with fresh water, odds a really good source of micros.
