"Margolis" wrote in message
...
"El Penguini" wrote in message
...

changing the water has no affect on the bacteria at all. The nitrifying
bacteria is not free floating, they are attached to surfaces in the tank
and
filter. You need to constantly change water in a tank while it is cycling
if you have fish.


The nitrifying bacteria may not be in the water, but the "stuff" (Ammonia,
and Nitrites) it feeds on is. New tanks do not come with bacteria built in.
It must be made. That is why you must stock the tank with a couple (and no
more than 2 in a 20 gallon.) hearty fish, and resist changing the water as
much as you can. If the ammonia or nitrates get high enough that the fish
are showing definate signs of stress, then a 25-50% water change should be
initiated. Just be warned, every time you change any of the water, you will
slow down the cycle process. Under no circumstances though should the tank,
substrate, or filter be cleaned during the initial cycle as this will
destroy any beneficial bacteria which is taking hold. Just to give you an
idea of what an unreasonable level is, I recently cycled a 20 Gallon Tank
with 2 African Cichlids. During the cycle my ammonia spiked at around 8.0
Parts Per Million(PPM) for about 3 days followed closely by the Nitrite
level getting up to 5.

As far as time frame goes, patience is a virtue. Regardless of what all
the books say, it will take the average tank about 6 weeks to be fully
cycled and ready to accept its next batch of fish. The Nitrite eating
bacteria alone doubles only every 15 hours and it needs to multiply many
times over before the tank is ready. If the books said this though they
would never sell.

After the initial cycle, the Nitrate level will be high. At this point
it is safe to do a partial water change; 25-50% depending of fish breed and
weather or not you have live plants or not. This will lower the nitrate
level which cannot be converted by any natural process except
photosynthesis. After the water change, fish can be added 1 to 2 at a time
each week or so until it has reached capacity. (as a general rule, a tank
should never exceed about 1" of fish per gallon) So be patient, and it will
pay off.


By the way, be aware nitr"i"tes and nitr"a"tes are very different.
Nitrites are very toxic to fish, most cannot tollerate more than about 2
PPM. Nitrates are also toxic to fish, but only in exceptionally greater
quantities (40 to 80 PPM or more for some fish).

Anyway, now I have rambled on for way too long, so if you are actually
reading this part of the message I would be very suprised.

-Steve