Re: Oxidized nutrients

[Thomas Barr <tcbiii at earthlink_net>]

> (!) Which suggest that weekly doses isn't the way to go, or am I
> missing something?
> To low DO-level = bacteria can't convert ammonia/nitrite to nitrate
> resulting in algae.


Frequently low DO means that your plants are not doing anything, e.g. -> no
plant production. Infrequently it can mean an excess of organic material
dumped into the system also or a massive die off etc. If you have not
noticed any die off of fish, added a bunch of rotting stuff, added a
considerable amount of something organic etc, it's unlikely.
If the plants are taken care of nutritionally, have enough CO2, light, they
should produce large amounts of O2, enough for fairly large shocks, but
everything has it's limits.

If you hurt the plants in one of those three areas, and add a large organic
load, things go sour fast.


If no production is occurring then obviously no NH4 is going to be
assimilated/uptaken etc.
Having a decent sized filter vs the critter load will help, but the knocking
the plants out will be a large issue. Bacteria are a good back up though.

> To high DO-level = nutrients get oxidized?
> Is this the reason you, Tom, dose every 2-3 days?

No, not really my reason but one could argue this point if they wanted.
I do it based on a couple of things I know about limiting nutrients in
algae/bacteria.

Most algae and bacteria are not affected by limitation for about 30 hours or
so in mediums of 0.00ppm nutrients etc. Then after that time, you'll see
signs of problems. 

Plants/algae/bacteria etc are fine up to this point but weak if you go
beyond this point. Keep going and the larger plants will die then the algae
and you'll be left mainly with tiny algae and bacteria.

But plants have a bit more reserves than algae and 2-3 days made no
difference in dosing than a daily routine which I'll never be able to keep
up with. Weekly seemed to be too long and _plant health_ was the goal here.

For myself, considering plant health alone was the gauge.

All the mumbo and jargon aside, that is likely the best single trait a plant
tank owner can have.

That was how I approached things, not through theory etc. That's a secondary
thing that I've been trying to go back and see how things can be explained.
Observe first, then try and figure the why.
 
> "I add every 2-3 days the following: KNO3, PO4 source, and a trace mix(TMG,
> SeaChem flourish etc). Weekly I don't get nearly as good results I feel."
> 
> The reason for my concern about nutrient oxidization is that I dose(d)
> weekly and
> the results were pretty good, but the last two weeks I have dosed TMG two or
> three times every week and the results seems to have improved. Same amount
> of fertilizer - better results.

So keep doing it:)
2-3 days will satisfy every one's plant needs even at very high light
levels.

You'll get a slower rate of uptake with less light and can adjust the
frequency of dosing to match by testing. Generally, the above will give very
good results.

Max NO3 uptake seems to be about a 4-5ppm a day
So dosing to 10ppm 3x a week is about right.
Traces seems best dosed every few days rather than trying for a whole week.

I have done well when dosing once a week with a low light tank, a 55 gal
with 2x 40 w bulbs/reflector. Less light, slower growth and things are not
so critical if you are out of something for a couple of days etc.

Regards, 
Tom Barr