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High nutrient levels

Mr. Barr wrote:

> >> Two weeks ago I added 8 Jobes sticks (16-2-6).  
> What I think might have happened here was hitting that magic point when a
> tank just starts to takes off.  *Plant momentum*, if you will, had just
started to take 
> off. Before things weren't growing to well then all of a sudden wham!
> Perhaps it was due to the sticks? Or was due to a stabilized balanced tank
> that had finally got going full speed? 

Hard to say, actually.  Tom had visited my tank a couple of days prior and
told me he thought it was just getting ready to kick into high gear.

> I think I'll go grab some Sticks and try it myself to see. I have a newly
set up flourite
> tank to try it on.

Orchard Supply Hardware, $1.49.  If I had it to do over again I'd look for
the standard houseplant sticks which have MORE phosphates than the 16-2-6
variety (for ferns).  My plants are growing well, and although I'm sure the
tank is phosphate-limited my testing indicates I probably tolerate a lot
more PO4 and STILL be phosphate-limited.

> Perhaps the plants(at least some of them) are now taking N from the soil
as well as 
> from the water column now due to the slower NO3 usage? 

I don't have Tom's experience, but I think this has got to be the case.  I
find that different plants have responded to the environmental changes in
different ways.  Some of the stems seem absolutely nitrogen-starved
(Limnophila sessiflora), while others are growing great (Rotalla macranda),
and I've been throwing away handfuls of Salvinia, a know nutirnet sponge,
every week.  I finally got smart and got rid of most of it.  My cute little
E. bleheri is no longer a small plant.  New leaves are 1.5" wide, tinged
with red, and at 10" long they still haven't stopped growing in length.  Be
careful what you wish for.

> I think it is interesting that Mr. Rubin's tank was able to absorb so much
nutrient load.

It gets more interesting, Mr. Barr.  By careful testing and watching the
plants' response to nutrient changes I had learned how to keep my PO4 levels
very, very low and my NO3 levels only slightly higher.  Bear in mind that
I'm referring to measurable nutrients in the water column, and that there
may be some transference or leakage of nutrients from the substrate involved
as well.  After reading Steve Pushak's recent post on PMDD nutrient target
levels it occurred to me that I wasn't providing enough NO3 - there were
symptoms among the plants to corroborate, such as rotten jungle val leaves,
chlorotic new growth on Anubias nana, and light (white, not yellow) color in
tenellus and sags.  So I began adding 1/4 tsp KNO3 per day to my 50g tank,
doubling my normal dosing rate, and I've been feeding the fish heavily.
Careful testing still shows minimal PO4 (0.05ppm - 0.10ppm) and slightly
elevated NO3 (2.5ppm).  The swords are darkening up and I'm seeing increased
growth elsewhere (Riccia, for instance), though I'm still waiting on the
Anubias and it's too soon to tell whether the vals are happier.

Don't get me wrong, I'm really enjoying the ride, but I feel like I've
created the Frankenstein monster.  At 2.2w/gal PC with CO2 at 24-30ppm, I'm
now feeding my 50g 5ml TMG every two days, 5ml Flourish Iron every two days,
1/4 tsp KNO3 daily, heavy fish feeding (flakes) and I leave a bag of
granular dolomite in the sump to maintain general hardness.  This, on top of
the 8 Jobes plant stick I placed 10 days ago.  So far no visible algae other
than the green-spot-on-the-glass variety.

I may have overbuilt. <g>

michael rubin