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Re: [APD] Why I do not have BBa in non CO2 planted tanks and CO2 enriched planted tanks with the same light intensity, same plant biomass, but different growth rates.

> Perhaps it would be more accurate to say that insufficient CO2
> for the
> amount of light and dosing leads to BBA.
> Bill

There are two things occuring here.
For non CO2 tanks: no BBA grows because BBA needs CO2, with good
plant biomass, light, well adapted plants to low CO2
conditions(which means no water changes which adds CO2!!), the
planted tanks do well. BBA is often found in places with 5-10ppm
of CO2 and good current in natural systems.

I've never had BBA in a non CO2 tank......... ever.

If you use some CO2, say insufficient or variable amounts on the
lower end, then BBA is highly probable.

The light can be the same for the non CO2 and the CO2 tank,
let's say 2.5 w/gal of NO FL's.

As light intensity goes up, so will CO2 demand, but the amount
needed will simply be scaled up as well.

You can compare the tanks with the same light intensity using
CO2 or not.

Plants take a longer time to adapt to low CO2 levels than algae.
But once they do, they dominate if you start the tank out with
good plant biomass.

Doing weekly water changes, adding filters, aeration etc is BAD
for non CO2 tanks! this provides a small amount of extra CO2,
but this favors the algae, not the plants, the demands of the
plants are not met when you do this, but it does help their
growth if you look at them in isolation.
The demands of the algae on the other hand........are met by
using aeration/water changes etc, they grow like mad with a
small amount of extra CO2.

BOTH plants and algae prefer CO2, so not doing water changes/not
aerating etc allows the plants to remove all the CO2 rapidly in
the tank, and it keeps it very low, plus the plants remove all
the NH4.

Result: slower growth, but.....no algae.

The algae are more limited when they have to use bicarbonate or
simply go into a spore stage and wait till there is ample CO2
available(which would also mean no competitors around using up
CO2/nutrients etc).

So they stop growing when there is virtually no CO2 available.
Same deal with NH4 vs NO3, plants might prefer small amounts of
NH4, but algae really do well with good NH4 at higher levels but
not NO3.

Both NO3 and bicarb can be used by algae, but they have to work
more to get it. Most adult calgae can continue on with therse
are nutrients sources, but most spores will not germinate.

So rather than working, they produce spores and wait.
You still need to remove any existing adults, but the concept
does apply well to explain why algae is not present in the non
CO2 tank.

This is obviously a much better theory than Fe limitation or PO4

As far as a CO2 enriched tank, a similar issue exist.
High CO2, or CO2 over a range, causes the spores not to
germinate, but the adult algae already there will continue to
thrive and grow. You can see this for weeks, months, years ever.

But you do not have any BBA outbreaks.

Why would the BBA not germinate spores with high CO2?
Simple, they are ina  great vegetative growing non limiting
environment. They can keep growing till times get tough.

Spore production and blooms are formed from changing conditions.
Just like when the weather gets cold, the rains come, the
weather gets hot and dry etc, most plants form seeds to make it
through hard times.

Same deal with algae spores.

You have an algae spore bank in your tank waiting for the ripe
conditions to prevail, then they germinate and bloom.

If you look at weeds and seed banks, there are many correlations
with aquatic plants and algae/spores.

Tom Barr


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