Join Date: Jun 2010
Location: Northern Virginia
Oh yeah, I definitely use fish water from water changes for my plants. Fish poop is awesome fertilizer, especially if you keep goldfish. It's the basis for a relatively new growing technique called aquaponics--you should read about it sometime. Very cool.
I definitely would not put noodle water in a fish tank--it would just foul the water. The plants would enjoy the shot of ammonia/nitrite/nitrate that might cause, but your fish surely would not.
As for the coffee grounds thing, I hear it is great for some plants acid-loving plants like azaleas, tomatoes, and rhododendrons, but you can overdose on them and not all plants enjoy the high acid content. Often it can make plants grow bigger, but not flower or fruit well--so it's best to use them sparingly.
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