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Re: Nutrients

Steve Dixon wrote:
> I saw your note on the APD to Chris re nitrates and nutrients.  I have been
> surprised by how much nitrate a well-run planted tank can tolerate. 

Thanks for the reply, Steve. 

Well...., I didn't want to bring it up, with the risk of being labeled a 
"bad" aquarist, but here it goes. My paludarium (frogs and newts) 
is usually passed up when weekly maintenance comes around, 
and here lately I had passed on it way too often. The hydrocotyle 
and riccia grow at exponential rates, all the time. No algae on the 
glass or on any of the plants. No algae eaters, not even MTSs. I 
hardly ever change any water and usually just top off any 
evaporation. On a whim the other day, I brought in a sample of my 
paludarium water. I ran PO4 and NO3 on it and was floored!!!! 
(Embarassment setting in...) The PO4 was ~5ppm and the NO3 
was ~250PPM! I about fainted. That's right, 250. The hydrocotyle 
(as you can imagine) is blooming every other node and the riccia is 
piling up. So, I never expected anything of being out of whack. 
There's always been a little earthy-smelling BGA on the wettest 
rocks (above water), but never any below the water's surface. Now, 
two weeks later, NO3 is ~25ppm and the PO4 is ~0.5-1.0ppm. All 
my little creatures are in fine shape and eating like lions. That's the 
problem, though. I feed the frogs and newts nightcrawlers and 
crickets from the bait store, but only once or twice a week. 
Shamefully, I will keep a better eye on the tank.

> You mention having spot algae with 5 - 10 ppm nitrates and 0 ppm PO4.
> Several of us here on the West Coast have observed that well-run high light,
> CO2 supplemented tanks often show a very noticeable benefit from the
> addition of small amounts (under 1 ppm) PO4.  This can on occasion include
> reduction of spot and other types of algae as well (anecdotal observations
> only).

I have a weak solution of potassium phosphate monobasic, and I 
usually dose about 0.050ppm every two weeks or so. I was scared 
to use it more often or to use more, since I already had some spot 
algae. I thought it would only increase the algae population. More 
nutrients=more algae. I guess it couldn't hurt to try. I'll observe any 
changes over the next few weeks and report back and findings: 
good (hopefully) or bad. I keep K levels around 20-30ppm, so PO4 
is all I'm lacking. Honestly speaking Steve, this is my only PO4-
limited aquarium. EVER! I've always fought to keep PO4 levels 
down, I've done it for years and years. Adding PO4 now is like 
sticking my hand in the fire. It just doesn't feel right ;-)...

Jamie    <"\\\><
Greenwood, SC