Re: of nitrogen and phosphorous
To: Aquatic-Plants at actwin_com
Subject: Re: of nitrogen and phosphorous
From: psears at NRCan_gc.ca (Paul Sears)
Date: Fri, 25 Oct 1996 11:31:01 -0400 (EDT)
In-Reply-To: <199610250739.DAA16186 at looney_actwin.com> from "Aquatic-Plants-Owner at ActWin_com" at Oct 25, 96 03:39:02 am
> * Subject: Of Phosphates and Nitrates
> * From: Calvin Chin <cfc at pacific_net.sg>
>1. Nitrates and phosphates usually go hand in hand inducing heavy algal
>growth. Supposing we manage to get rid of phosphates in the aquarium but
>Nitrates are still present. Will Nitrates alone be sufficient for algae to
>grow? Which is a better nutrient for algal growth? Is it Phosphate, or
>Nitrate, or are both needed?
It seems that all the algae need phosphate, but that the
blue-greens (cyanobacteria) can do without nitrate. See
Dave's posting. As numerous people have reported, you can
have a fair bit of nitrate without algae problems
>3. Supposing the regime as prescribed by Paul and Kevin works, does it mean
>that I can do away with the bi-weekly water changes and just change water
>only when phosphates go out of control?
I would not do this, and we recommended water changes in our
article. The water changes prevent the buildup of things other
than phosphate - the phosphate is removed in plant material thrown
out. The whole point is to use the _plants_ to control phosphate.
>5. Instead of adding Nitrates, will it be just sufficient to increase the
>feeding of my fish (relying on the extra Nitrates produced.) But I also
>understand that phosphates will no doubt, increase.
I suspect that, in many cases, the ratio of N/P in fish food
is low enough that the _nitrogen_ runs short, and the tank has
too much free phosphate in it after a bit. The result would
be algae, and plants that do poorly.
>because Paul and Kevin's theory will really revolutionise
>things if it is indeed true (read no more water changes?).
In my opinion, this is asking for trouble.
Paul Sears Ottawa, Canada
Finger ap626 at freenet_carleton.ca for PGP public key.