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Hi

As many of you may know Australia is currently experiencing a long drought and i read an article about the gov't limiting the amount of water you can use (i dont know if this is actually gng to eventuate) but i was wondering if anyone has any good suggestions on reusing tank water?
i water the garden with it at the moment but was wondering if there was a way to filter it (maybe by pouring it from one bucket through a thick wad of filter wool into another bucket ) and then be able to place it back in the tank ?

just a thought

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Truth doesn't always win friends but it influences them

Mechanical filtration is not your problem. If the tank is already filtered then any particles you can remove that way will already be gone. The problem is water changes are normally done to lower nitrates and nitrates are too small to be removed by most anything but an RO system. The only way to really lower nitrates in a given amount of water is to use plants. You can setup a heavily planted tank or container and place water from the fish tank in there. The plant growing container doesn't exactly have to be an aquarium or even clear since it's purpose is not so much for looks. The plants use the nitrates and then you put the water back into the tank. Requires lots of plants and lots of light though. Plants like duckweed and hornwort in a container sitting in an area of sunlight might work. Even then it wouldn't be enough for a well stocked tank unless you have a very large plant growing container but might help.

Another way of approaching this problem is to remove the need to take out the water in the first place.

One interesting system I've seen documented in the aquarium magazines is the "vegetable filter" - in effect, a refugium containing lots of plants, whose purpose is to soak up nitrates and phophates as fast as the fishes can produce them.

Such a filter involves the use of fast growing plants such as Hornwort, Ceratophyllym demersum, which absorbs nutrients throughout its entire volume, Phyllanthus fluitans (which is regarded as an excellent ammonia and nitrate absorber) and Amazon Frogbit. The main aquarium is connected to this, and water flows in at one end from the main aquarium, passes among the plants, then is taken from the other end back to the main aquarium. The vegetable filter also provides a place to cultivate creatures such as Gammarus and Crangonyx freshwater amphipods to be harvested as live food for the fishes, and a safe place to rear out baby ornamental shrimps where the fishes won't eat them if this is desired also. Basically, it's the feshwater analogue of the refugium systems used for marine aquaria, but instead of having to rely on macroalgae (and carefully chosen ones, as Caulerpa has some issues associated with it) the vegetable filter in a freshwater setup relies on higher plants, and the vegetable filter can, in turn, be used as a safe haven for rearing fish fry until they're big enough to be transferred to a purpose constructed nursery.


Panda Catfish fan and keeper/breeder since Christmas 2002

There are people doing this in plastic 44gal drums (available at horse feed stores) and just dumping the old water in and letting it rest for a month or so.

Some are using plants in there (marginals supported on boards and chains, they work very well) and some are just using the old 'set it and forget it' method.

I have no idea how it works, but it seems to be fine. They are using it in drip systems with halfmoon bettas and they are pretty sensitive to dodgy water so its got to be reasonable.

Maybe half and half it with tap water?

For animals, the entire universe has been neatly divided into things to (a) mate with, (b) eat, (c) run away from, and (d) rocks. - Terry Pratchett

Hi,
While I've heard of Calil's "Vegetable Filter," I don't
recall ever reading about how big they should be.
I know the light cycle should be the opposite of the main
tank so that when the main tank is dark, the second tank
should be fully lit.

However, I've never seen anything about how big the other
tank should be. If your main tank is 55G should the second
tank also be 55 or would a 30G tank do? Nor have I seen
anything on how much "plant load" should be in the second
tank to compensate for "X amount" of bio load in the main
tank.

You would also have to establish a system to replace the
trace elements that the plants, and fish, need for growth
without encouraging an algae breakout.

You are not going to be able to create a "perpetual
machine" out of your aquarium. In nature, the water
supply is constantly being replaced through some sort of
water source replacing what is evaporated or sinks into the
ground. You can lower the amount of replacement water
necessary however.

IN theory, the system could, maybe, work, but there seems
to be allot of unknowns that would have to be worked out
to reach a workable system. Actually, you are simply
creating a second tank, tied to the main, and thus
increasing the total amount of water in the system.
Many have done this to compensate for overloading the
main tank. Or, to allow them to overload the main tank for show purposes.

Frank

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