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Re: Cycling

>Subject: Re: Cycling a new tank
Susan Romano wrote:

>Ammonia is called ammonium in water with a PH less than 7. 

Not quite accurate.  Ammonia and ammonium exist in equilibrium.  There is
more ammonia at higher pH levels, more ammonium at lower pH levels.  I'm
sure the chemists on the list could elaborate.

>In this state it
>is food for plants and tanks that have plants make this cycling stage safe
>for fish. The stem and other fast growing plants are more efficient in
>extracting ammonium directly from the water column and are the ideal
>starting plants for this reason.

It isn't the fact that they are stem plants, it's the fact that they are
fast growers.  Fast growers, given good growth condition tend to extract
_all_ nutrients from the water column more quickly.

> If there are not enough of these fast
>growers then the end product in the water is nitrate which is food for
>algae as the higher plants absorb nitrate through their roots better than
>from the water directly. Some floating type plants such as riccia can take
>in nitrate directly but most don't. 

This is incorrect.  There is no evidence that I know of to suggest that
_all_ plants can't benefit from ammonia, ammonium, nitrite and nitrate.  It
is true that studies have shown that plants will preferentially take
ammonium first.

>When you start getting nitrate readings
>on your test kit, start doing small daily partial water changes until the
>nitrate readings are almost 0. At that point you can start adding new fish
>gradually if you wish to.

Better yet, plant the tank densely from the start, provide good conditions
for growth, and don't add fish that need to be fed (i.e. anything but algae
eaters) for the first month.  Then, as long as you don't overstock or over
feed, you don't ever have to worry about either "cycling" the tank or the
buildup of excess nitrate.

Karen Randall
Aquatic Gardeners Association