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Green water notes/NH4

> Tom wrote:
>> I add about 1/4 teaspoon of KNO3,
>> Yes, I can. There may be a NO3 limitation
> Is there a difference with KNO3 and NO3?

Well yea, the K+. You can add other sources of NO3 ion(sodium nitrate for
example). Most of us use KNO3 though as the extra K helps.

I think what I was saying is that your tank gets GW from being so low in
NO3's. The bacteria in your filter that converts NH4/NO2-> to NO3 is being
starved and/or does not have enough biomass for the inflow of NH4 that your
tank produces or the extra food your adding, jobes sticks that get pulled up

 So when you clean your filter out too well with high lighting such as PC
this adds a slight spike of NH4/NO2 and the algae senses this and blooms
like mad to get a jump on the rest of the algae for the food(N). GW are
"early germinators" trying to get a fast jump on the rest. Once there, it
Filter less tanks are often plagued. New tanks that are not established yet
are plagued. Tanks with a clogged filter or very little biofilter are
plagued if they have the high PC output lights.
If you disturb the heck out of the substrate-> GW. But you need a poor
biofilter and PC's or/and chronic low NO3's that allows for a weak bacterial
colony. Bacterial mass is going to be much lower in a NO3 limited tank.
These seem to cause GW in all the cases I've seen. Just look at the trend
for the cause. I think it's pretty clear.

I recently took care of an idea that I thought would work to this end. A
small tank(20 gallons)that had chronic GW. Black out for 5 days. Added KNO3
prior to blackout. Added mature good size filter(Magnum HOT that had not
been cleaned for months containing biomedia only). The GW has not come back.
I added all sorts of things, High KNO3, loads of TMG, iron, PO4 etc. Plants
are growing like mad. Been 2 weeks now. In previous test the GW always came
back time and time again. Levels of the nutrients where the same.

 Now if I add a jobes stick to the water column in there guessy what
happens? Guess why? Guess why I don't use jobes anymore?
 I have not yet tested the NH4 but will next. I bet a bunch of noxious weeds
that you'll see a slight NH4 spike in every GW outbreak. How much? I don't
know but a little one does exist is my bet. That's the signal for the
desmids to multiply if they have enough light(and all the other nutrients
that we add).

1) Lack of or too small of bio colony->get bigger filter/add bioballs etc
2) colony needs fed and so do the plants-> KNO3
3) Clean filters out that get clogged
4) Do water change after a big hack
5) Keep the NO3 levels in good shape.

Some folks have said they don't want their bacteria to compete with the
plants and use the NH4 etc. They say they have increased growth etc. But
there a trade off. Adding more fish food and KN03 will take care of that
just fine and you'll still get good growth with much less chance of GW algae
outbreaks. Perhaps other types of outbreaks as well. But I'd rather have a
little bacteria doing the competition than GW personally.

We've had this discussion before. I've been looking at this algae a lot over
the last year or two. SFBAAPS list has been going over this issue lately
also with a very chronic case in a 10 gallon tank with PC's. The owner is
very good about testing and trying things to kill it. My bet is that if the
filter is upgraded and he kills the GW with a  Blackout/UV etc it won't come
back. I tried it and it's ahh...clear as day to me.

Tom Barr 

> Dave Berryman