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Re: Water changes/N & O2 / fish load

> IDMiamiBob at aol_com
> Subject: Re: Tap water conditioners
> Okay, now here's a quandry- We do water changes to reduce nitrate levels.

I don't. 

> But if we have chloramine in our water, and we use it for water changes, we
> are re-introducing ammonia, which is converted by the filter bacteria to
> nitrates. 

If the plants don't get the ammonia first(if in fact the converted form is
available to them), as they do like it/prefer more than the Nitrate. If you
don't have a filter(the plants in many tanks are the "filter") then it's
just the substrate and a few surfaces that the bacteria grow on. Most of us
tend to have small filters compared to fish only tanks. The ammonia never
gets much chance to be converted into nitrate before getting sucked into the

 Amquel doesn't really "remove" the ammonia, it simply binds it and
> then releases it slowly.

Good plant fertilizer then? Maybe those big weekly water changes are the
trick. Amano says in the books he does them too.

>How do we reduce the nitrates under this scenario?

Many well run tanks operate at deficient nitrate levels(they need extra
nitrate added). The notion of adding KNO3 to one's tank come into the
picture at this point. They can use the extra K+ and this can be a quite
high level with great growth and no algae.
Raising it to about 5-10ppm NO3 seems about right for many folks.
You can also have more fish.......up to a point..... to supply this extra
NO3-/NH4+(more on this later). I like lower NO3 levels and high everything
else(traces, P, K+,CO2, light etc) but I make sure to add a good amount of
food hoping to get lots of NH4+ in there instead of NO3 so the plants get
fed some source of Nitrogen, the preferred form, NH4+. This takes care of
nitrogen deficiencies(it has for some time now in my tanks) and lets me get
away with lower NO3 levels(0-2ppm).

I don't have any experimental data, just observations so far but it sure
seems to work well and matches much of what I've seen playing with
nutrients. There is better plant color and less (much) glass algae as a
result and great plant growth still. I'm still skeptical though, too many
blunders and mistakes over the years:)

    *About that fish idea........

Respiration takes place in both plants and animals, correct?
If you have no fish depleting the O2 and the adding to the BOD(Biochemical
Oxygen Demand) of a closed system, will the O2 levels be higher when the
lights come back on in the morning or lower?

Higher, right? Less things using the O2 keeping the O2 from falling down to
lower concentrations.
    Fish use it up quite fast as we all know on the APD (how long after the
power goes out will my fish all die?). Based on weight and mass, fish use
far more O2 than the equal amount of plants.
What does that mean for the plants and their growth and health etc?
More O2 for respiration at night and the morning till the O2 gets up to the
saturation point, which would equal better growth for the plants.

Biology is all about trade offs and balances. No different here. Too few
fish no NH4+ sources(I *think* the Amquel idea does not add much, you would
need to do lots of water changes it would seem)

Amano adds O2 to some of his tanks with the beetle diffusers. The H2O2 thing
and the redox thing got me buggin on this idea too. Ozone and few other
additives(H2O2 etc) will lower the BOD and raise the O2 levels by lightening
the load of O2 demand. Many many folks have found all over the world and
through the years that low to moderate fish loads work the best for planted
tanks. Even to highest tech, well maintained plant tank will have problems
if the fish load is too high...unless maybe you add 02 gas( the other forms
are asking for trouble I think....H2O2, O3 etc). I'm sure you can overdose
the O2 and perhaps get bubbles forming in the eye like with trout in some
public displays that have deep water cold well aerated water which super
saturates the water in some cases and other problems.

 Adding O2 gas directly or keeping your fish load low enough, but not too
low, seems to be the idea here I am getting at.
I think that this a good notion on why it keeps algae down and plants
growing well regarding "that fish idea".
BTW, snail loads and shrimps loads etc count here too.

Low O2 can hurt plants as well as fish but the plants are much slower to
react(days to weeks compared to hours or minutes in some cases)
O2 is the forgotten gas that the plant needs. We all tend to be so concerned
with CO2 so often. I wish I had bought that O2 tank for 10$ at the flea
market awhile ago:(


Tom Barr