Aquarium waste water

by Janet
(Burnaby BC)

For years I've used my aquarium waste water on house plants or container plants, but it was for water conservation (rooftop garden with no rooftop tap, so might as well re-use this water as any other). But recently I saw a post somewhere referring to waste aquarium water as "compost tea", and that this person's garden had danced for joy--so to speak! I've certainly never noticed any such rejoicing, but now I'm wondering if I should use it in the dry/barren under-the-spruce-and-cedar-tree areas. What do you and your readers think?

Doug says that it isn't "compost tea" in any sense of the word. My guess is that if the filters in your aquarium are working, you're removing the nitrogen (or your fish would soon die) and most of the other "nutrient" compounds (activate charcoal filters are extremely effective at sucking out many materials)

So - for the amount of water you're replacing or tossing away, I rather doubt it's going to make much difference whether you use the aquarium or the downspout water.

But I haven't measure the fertilizer value of fish water.

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Aquarium waste water

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Turtle waste water
by: Anonymous

We use the turtle water/waste here and throw it in the garden and the roses on the rose bush look like they are on steroids...its amazing

Why not...
by: Anonymous

Actually, another thing I forgot to mention....there is NO aquarium filter medium that absorbs Nitrates. I can't say for sure but from all the aqaurium forums out there, I can't find any Nitrate absorbing products that people have said worked (unless they were somehow selling the product). This is what forces fishkeepers to have to keep changing water...so the activated carbon nor the Meshes nor the chemicals actually remove the nitrates from the water.

so, you don't need to think about the filters removing nitrates from the water.

Why not....
by: Anonymous

First of all i should say that I'm not a chemist or scientist of any sort...actually, I'm an accountant but an avid fishkeeper.

Now, the first thing to note is the nitrogen cycle in the aquarium. Fish excrete/secrete ammonia. In a healthy aquarium, this ammonia is quickly converted/digested by bacteria into Nitrites. If this does not happen, the Ammonia will kill the fish. Then, the Nitrites are semi-quickly converted into Nitrates by other bacetria. The bacteria above are all aerobic bacteria, and so do a good job in an aerated aquarium (most are, as a healthy aquarium needs oxygen for the fish and to get rid of the Nitrites which is also toxic to fish at moderate levels).

Now, the last part of the nitrogen cycle is that Nitrites is converted into Nitrogen gas and this is done by anaerobic bacteria. In a healthy aquarium, this does not happen quickly as the conditions in a healthy aquarium do not allow for anaerobic bacteria to thrive. So, in most aquariums there is a glut of Nitrates in the water. This is "bad" for the fish but only at high concentrations. But this is one of the main reasons why, fishkeepers needs to change the water every one in a while. To keep the Nitrates down.

Now back to the plants, I don't actually know what can be used as a fertilizer for plants, but I think all forms of nitrogen can be used...ammonia, nitrites, nitrates (and whatever solid form of nitrogen itself). So, if the plants you have in the yard can thrive on Nitrates then great!! Aquarium water is full of it....but if it needs ammonia or Nitrites then maybe not so good....but at the very least, the plants need the water anyways.

Michael

aquarium water
by: Pansy

Re: aquarium water. We have two turtles and in the summer I water the garden as much as possible with 'turtle water' when cleaning the tank/pond. (The filter for the tank doesn't have charcoal, merely a sponge filter). The plants in my garden are pretty lusty -- I attribute it to the turtle water.

Aquarium waste water
by: Anonymous

Thanks Doug-- that makes aquarium water change day a lot easier. You're right of course about the nitrates--hadn't thought of that. I don't use activated charcoal... But now I wonder about the one bucket's worth that the filter gets cleaned in-- nasty muck, much nicer to just throw in the toilet!

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