Re: Aquatic Plants Digest V5 #450

[David Marshburn <marshbur at cs_unc.edu>]

On Fri, 22 Nov 2002, Aquatic Plants Digest wrote:

> Date: Fri, 22 Nov 2002 09:46:10 -0500
> From: NightFlight <ecwh at cogeco_ca>
> Subject: Sodium Hydroxide in local drinking water.
> 
> Also, I don't have a source of  K+ or P04. How about using small 
> banana fragments? Just a shot in the dark.

Well, I thought about using banana processed through fish tummies as a
source of potassium in the tank.  Wiser heads talked me out of that and
suggested potassium tablets.  I'm using Potassium Gluconate tablets from
GNC (a dietary supplement store found in many shopping malls in the U.S.;
you may have something similar or the same things in Canada).  Anyway, the
reason I'm so enamoured of the particular pills from GNC is that they
aren't caplets (so don't have that plastic-ey shell) and contain nothing
other than the potassium gluconate and dextrose (a sugar).  Looking in
some drug stores, I found other potassium gluconate pills, but they all
contained loads of other ingredients (some of them involving copper, which
I wanted to avoid out of concern for my apple snails).

Anyway, a bottle of 100 pills was $4 (U.S.).  Each pill has 99 mg of
potassium.  I've been adding 2-3 per day to my 50 G tank, and my Rotala
loves me for it (turned from a nasty yellow-pink to a very bright red).
I just add it to the top of my filter media in the filter outflow, and let
them dissolve there (I tried grinding the pills up, but it was a pain, and
this is just as effective).

I never did figure out the potassium content of a slice of banana.
http://www.banana.com/nutrition.html says that a 9" banana has 602 mg of
potassium.  Adding, say, a 1/2" slice per day would add about 33 mg of
potassium to the tank.  Unless you have a lot of fish that love banana,
this may not prove to be a viable source.  There'd also be the issue of
plants absorbing the potassium through the fish waste (I don't think this
is generally a problem....).  Also, my $4 bottle of pills will last me
about a month, and $4 of bananas certainly won't keep that long.

Good luck!

Cheers,
-David