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Re: Cycling a new tank

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

NH3 is ammonia, while NH4+ is ammonium.  The amount of NH3 relative to
NH4+ is dependent upon pH.  The following table lists the percent of NH3
at 20 C and varying pH:

pH	%NH3
7.0	0.40
7.2	0.63
7.4	0.99
7.6	1.56
7.8	2.45
8.0	3.83
8.2	5.94
8.4	9.09

There is very little ammonia at pH < 7, and it doesn't become prevalent
until pH > 8.2.  Besides, it's the ammonia concentration, not the
relative proportions, that's important.  A new tank with 1 ppm NH3-NH4+
at pH 8.0 is less of a problem for fish than a tank with 8 ppm NH3-NH4+
at pH 7.2.  Simply keeping a low pH is no guarantee for avoiding new
tank syndrome.

>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. 

Ammonia is actually more readily taken up than ammonium, as an uncharged
ion can cross a membrane more easily than a charged one.  This is
precisely why ammonia is more toxic than ammonium--membranes are much
more permeable to ammonia.  High ammonia is toxic to plants, too.

>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. 

Er, I've been adding nitrate to maintain 3-5 ppm in my tank for three
years now, as have many people on the APD.  I don't have an algae