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Re: Alage, bacteria, nutrients, allelopathy

I have to respectfully ask Tom to separate some of his points.   We can all
learn something at the end.
>> Recently I set up a new tank and densely populated it with lots of plants
>> (including several fast growing stem plant species). 

NEW TANK is one key point of this green water discussion. 

>> I also gave the tank a small (non toxic to fish) amount of
>> ammonium, NH4+). 

Small amount of ammonium plus AMMONIATED compounds from my "de-clorimated"
water was the other. 

>Almost a guaranteed prediction especially on a new tank and on a tank
>without a filter. Even later, you'll still produce GW until you get that
>filter on there. You do not have to even add NH4 in many cases.
 Let's clarify:

Are you saying that the GW combo is: new tank, NH4 and no water movement?

I now have a filter on the tank. I also have a diatom running today and the
water is crystal clear, so almost all, say 99.999% of the suspended algae
has been removed. It probably has less than any typical tank at the moment-
just because you dont see it, doesnt mean its not there....it is
microscopic. I suspect, however, that the algae has left something in the
water that allows it to re-populate, until I run the diatom a few more
time. I suspect it is something chemical.

>Consider this: High PO4 levels have not been found to be a direct cause of
>algae so you cannot blame the PO4 for the algae out break(it happens at both
>a high and low PO4's).

Algae does not need much PO4 to establish. It just needs SUFFICIENT water
column PO4, together with other desireable conditions.

>The pattern I've seen is GW followed by staghorn algae. GW blocks out a
>number of other species of algae but not staghorn(Entromorpha sp).

This effective competition may be related to chemicals.

>Another element or source of NH4 is uprooting a large plant. The substrate
>is fairly reductive and holds some NH4+ in many tanks.
>If you do a water change and remove most of the detrital matter with a fine
>net you can escape this.

Uprooting also releases substrate bound phosphates.

>I believe GW blooms have little to do with uptake of "excess nutrients"
>except for NH4 exclusively.

I agree that the NH4 is a factor. I can get green water by adding too much,
although safe-to-fish amounts of NH4 to a tank. The suspended algae seem to
get off on it. Their cellular uptake must be very quick, and much faster
than the plant. At least enough of them get fed and start to multiply.  So,
the AMOUNT of NH4 put into the tank all at once may be the key. Small
amounts from fishes, are fine. Small amounts from a water change , even
from the cloramines, are fine. Large amounts from substrate as you suggest
or from fertilizers is not. 

>If you perform large water changes there will be few allelochemicals. 

Water changes reduce the concentrations -- they dont eliminate them.

> Allelopathic chemicals are not a bad investment for a terrestrial plant but
>for an aquatic it seems like a bad idea except at low  easy to produce

Aquatic plants and algae produce allelochemicals. If a bad idea, why do
them have them, even at low levels.

>etc. Speed is the key to many of these "weeds".

Competitive edge may be small, but some edge is needed to allow one plant
to become dominant. Although each plant produces a small amount of
chemical, when they get to be large numbers, the concentration increases
greatly. That may be what the suspended algae leave behind after the
effects of diatoming or flocculants. I think I will do a large water change
now that my GW tank is clear.

>> I believe that my tap water
>> with chloramines is another source of NH4 (after treatment with chloramine
>> remover, the bound NH4 is treated harmless, but somehow its nitrogen gets
>> to be available to the plants ).
>This has been speculated and I think it is a very small effect to plant
>growth. If the contribution was larger, you'd get more algae blooms the
>larger the water change. We do not see that pattern.

I said the plants get nitrogen from the bound NH4. The prime creates an
ammoniated compound. This may  breakdown  gradually, so, it is not the same
as the equivalent NH4 concentration.

>Some tanks are more sensitive for a number of reasons. Filterless tanks are
>very sensitive and as they get larger, this can be come even more difficult
>to deal with.

I once had my 125 gallon tank without any filtration for 6 months. It was a
5-year old tank. The plants did not suffer in the least, neither did the

 Some tanks are tetering on the brink already, not enough CO2,
>bio filtration, too shallow a substrate(2" or less), highly limited and
>stunted plants etc. You add NH4 to those and your sure to get problems in a
>bad way.

Again, I was talking about a new tank, where everything was OK, except for
the fact that the plants were just moved into a new environment, and given
a little NH4. Under those circumstances, without established nitro bacteria
to help consume the excess NH4, the plants could not suck it all up....
leaving some residual to feed the few suspended algae cells that all water
must have. This is what I think caused my GW. I think the filter would have
only provided backup to avoid excess NH4. 

What about the fact that the plants were just moved. At the conference,
Amano (thru  translation) said that when plants are moved, they are
temporarily "in shock."  WDYT? I cant remember if I noticed this before.
Certainly not when they go back in the same tank.[Maybe this should become
a new thread?]