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Re: Discus and dinner

 From: George Booth 
Tom Barr wrote:
> > Well I can tell a thing right off the bat. High NO3 's are a
> > factor of not enough light and/or CO2 and/or plants. 
> >
> > <Do stuff to make your plants grow well>
> >
> > Do this for about 3-4 weeks then you should likely be doing
> > well.
George wrote:
> I have to respectfully disagree. 
> Planted tanks with large fish or a high bioload may indeed be
> nitrate generators 
> no matter how many plants are in them and how well they are
> growing. 

True, I stand corrected:) 
I wrote also:

"The Nitrate remover certainly is not the answer. A plant filter
would be another option if none of these methods work FOR YOU,
these plant methods do work though. Plants "eat" 3 things:
light, CO2 and nutrients.
Balance these and you'll be alright.
See if this helps.

Now depending on how FAR I wish to take the plant filter thing I
could have as many Discus as I wanted almost in a 100 gallon
tank, say 20, have a few big plant filters under there and there
wouldn't be very if any NO3 if a plant filter was set up. I did
do this many years ago. I had more fish than anyone would ever
think to put in a 100 gallon tank. Maybe 400 inches or more of
Big clown loaches, Fire eels, rare pleco's, SA cichilds, and a
bunch of other odd ball FW fish. I could not measure any NO3's
but the test kit was a cheesy Tetra kit. My vines in the plant
filter grew like gang buster(3-6 inch daily *terrestrial*
growth).If the power ever went out the fish would have a rough
go if I did not immediatly add supplmental air by way of a
battery back up:) Forget that. I needed more tanks:). Thank god
I got rid of the fish addition.
Too much worry and stress. I like low fish loads where if the
power goes out nothing to worry about for a day or so:). The
biggest issue is lack of NO3 for many of my tanks. Food is good
for adding that IMO.   

But back to George's point.
I should have said and made it clear:

"If you still have high NO3's, water changes, Plant fliters,
lowering the fish load should take care of things."

But plants can cure all that ails thee IMO. I don't always cover
all my bases here on the APD but try. 

Both our 
> 100g discus tank (4 adult discus and a handful of cardinal
> tetras) and our 120g 
> Rainbowfish fish tank (a dozen fish of various ages) need 50%
> water changes 
> biweekly to keep the nitrates in the range of 10-20 mg/l.

"biweekly" meaning once every two weeks? I hate this obvious
stuff:). Over my head sometimes. I had 5 Blues and 15 Congo's
and a few other cleaner fish in my 90 for awhile and it stayed
in the 10-15ppm range but I also added KNO3 after a water
change(weekly @ 1 teaspoon of KNO3). I fed them livbe brine
about once a week for about a month then got them on Fz
Brine/flake from then on. They were fed moderately. I do big
water changes(50% to 60%) in that tank. I also had a lot of
Riccia and some other fast growers and 2 x 175 MH's over the
tank. I got the wet/dry thing too.

> each tank, we feed 
> two frozen cubes 3 days a week, assorted dry foods on days we
> don't feed cubes 
> and skip feeding one day a week. When available, we feed live
> brine shrimp 
> instead of cubes.  
> I don't know if this is "heavy feeding" or not, but the food
> is consumed in 30 
> seconds by the discus and instantly by the Rainbows. We're not
> likely to reduce 
> the amount of food, either.

I would not call this heavy.
> You might say "It's the damn trickle filters. They are
> converting wastes before 
> the plants get a chance." No, it's the feeding. 

No,I wouldn't:)I know better:). I agree 100%.Trickle filter
good, algae bad.

Our other 100g
> tank with 5 M. 
> praecox and assorted housekeepers maintains nitrates at around
> 5 mg/l with 
> monthly 25% water changes. That tank gets half the food of the
> other tanks. 

Sounds about right.

> Has anybody ever quantified how much ammonium a fish generate
> per ounce of body 
> weight or whatever usful meadure there is?  Has anyone ever
> quantified how fast 
> plants can consume ammonium?  Has anyone ever compared
> relative uptake or 
> conversion rates of ammonium between plants and nitrifying
> bacteria?  I think 
> these are pertinent questions.

VERY big questions to me!Mass of plants would need to quantified
and many other variables but it should be workable. The Nitrogen
cycle is the big one I think. Much has been done on the P, FE,
and other elements. A lot has been done of the nitrogen cycles
also but perhaps not too much on this situation or answering
these questions?

> > George, I know you mentioned that your tanks routinely have
> 10-20mg/l
> > of nitrate.
> >
> > I'm curious as to why, since your tanks have high lighting,
> and CO2, and
> > are pretty densely planted (particularly that rainbow tank).
>   In my 75g,
> > if I don't add KNO3, within several days, the level will be
> zero.
> The two tanks with nitrate problems have some pretty big fish.
> How does the 
> relative mass/bulk of your fish compare to mine?  Are we
> comparing two pounds of 
> fish to a half pound?  

Great point. Well trimmed plant mass is also going to use less
than the overgrown more massive growth found in some untrimmed
tanks IMO.
Then there's snail mass, gravel substrate mass(all dat
bacteria), shrimp mass, flatworm mass, Daphnia, old tubifix
worms crawling under there:), filter area(more bacteria, snails
and anything else that might infest the filter)and anything else
that might contribute to the BOD of the system besides the

(BOD=biological oxygen demand-a bio term and water treatment
term commonly used) 

> > As for feedings, I feed my rainbows like the pigs they are! 
> Do you use any frozen cubes? My impresion is that a frozen
> cube (2 in fact) might be a lot more 
> food than a pinch or two of dry flakes.  

Me too.

I've always felt that
> maybe two cubes 
> is too much but Karla controls the feeding (the fish and me

Two cubes a day is all she lets you eat?:)Come to think of it, I
did swallow some thawed brine once when I used to pre-thaw it in
a cup. I had the cup sitting next to my drink also in a
cup....you know what happened next.......
I wasn't hungry for some time after......

Tom Barr

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