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Supplementing PO4
Steve Dixon wrote:
>I'll let you all in on a little bit of heresy I've been experimenting with
>recently. Many of us strive to maintain phosphate-limited conditions in our
>planted aquaria. This is one of our basic algae control strategies. But
>what do we really mean by that phrase? Can there be such a thing as having
>too little phosphate? And what does fish feeding have to do with this
>issue? Will a heavy feeding schedule provide sufficient phosphate for
>"optimum" (uh-oh, I'm in trouble now :-)) growth. My preliminary
>observations are that one can have insufficient phosphate levels and that
>this condition can occur in tanks where the fish are fed heavily!!! I'm
>using 1/10 gram amounts of potassium monobasic phosphate with quite
>surprising results (beautiful, is actually the right word for it) under a
>variety of high growth conditions. I have a fairly good feel for what this
>supplement is doing to nitrate levels (driving them down, as one would
>expect). I'm just starting to focus on the effect on potassium levels.
Funny thing. Karl Schoeler and I were recently discussing this very thing.
Both of us had observed that our Rotala macrandra seemed to take a hit if
PO4 levels dropped too low. In the last year or so, my town has started to
add phosphate ot the water to protect the pipes. I had been dreading that
day for several years, as I'd heard of other people having problems
maintaining planted tanks without algae problems with phoasphate in the tap
water.
I have found that with .5 ppm phosphate in the tap water that not only do I
not have algae problems, but in high light, fast growth tanks, the plants
perk right up with a water change... a phenomenon I attribute to the influx
of PO4. Even when I set up a new tank, I haven't had algae problems, and
that initial .5 reading quickly drops to undetectable in the tanks.
So I guess, heresy or not, I agree with you ;-)
Karen