Question: freshwater aquariums

Question: freshwater aquariums

One of my other hobbies is keeping two freshwater aquariums. When I do a partial water change, it feels like such a waste to put the water down the sink. So. I know that aquarium plants like nitrates, but what about my flowers? - The fish are betta, tetras and cory cats (corydoras catfish) - They are all fed Hikari foods (micro pellets, bio betta gold and algae wafers) - There is NO salt added to the water, though I do use a water conditioner (Tetra AquaSafe) The pH level hovers around 8.0 (our water here is very basic), the aquarium is fully cycled (ammonia and nitrites are at 0 ppm) and the nitrites are at about 20 ppm. I mostly grow roses and veggies, but I doubt I'd use it on the veggie garden for fear of chemical contamination. So guys, what do you think?
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