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Re: NO3 losses



My contention about the plants using up NO3 and not bacteria in significant
amounts is observed many times.

Consider when folks raise their lighting levels up.
They change nothing in their gravel/filtration etc.

Before, they never had to add NO3.

Now with increased lighting and hence increased plant growth suddenly the
plants are taking up much more NO3.

The substrate is relatively similar in both cases.
So if denitrifying bacteria were doing a significant amount of NO3 removal
in a planted tank, why was this not the case at lower light?
In a number of lower light tanks NO3 can build up. So the idea the bacteria
somehow make up for differences in concentration build of NO3 seems
unfounded. Bacteria can and do live on next to nothing so they are much
better adapted to deal with very low levels of a nutrient substrate such as
NO3 than say, a plant is capable of.

There are no photosynthetic prokaryokes that are denitrifyers that I'm aware
of. 

So the light should not directly cause anything concerning the bacteria,
except perhaps less NO3 in many/most cases from plant uptake only.

So adding more light should not effect them? And only effect the plant
uptake rates?

I still say the plants are doing the deed here and that the denitrifiying
bacteria only play a very small role.

I think vacuuming is a source but there are folks that don't vacuum at all,
I did not for a few different tanks. Filter cleanings is another.
Pruning/leaf removal etc doesn't count since it's plant parts.

Regards, 
Tom Barr