>Cary what is the KH of this designed water?
My tap water KH is 15 DH.
I normally don't add any buffers, but my experience has shown me that
the amount of calcium required seems to be dependent on total
dissolved solids. By adding a buffer you'd be increasing the total
dissolved solids, which would lower the percentage of available
calcium.
Here is my theory-
I tried to find a minimum level of calcium required for rainbows, but
ran into a couple of problems. As I changed the TDS level, the
required minimum level of calcium has changed. In softer water (lower
TDS) the required calcium level goes down. In harder water (higher
TDS) the required minimum calcium level goes up.
I'll assume most of you know, freshwater fish absorb water and must
constantly pump it out of the body. The lower the total dissolved
solids, the more water the fish take on and must pump out of the body.
It appears to me that this in take of water is also carrying with it
calcium and other trace elements. As rainbow fry have next to nothing
for skin or scales to protect the inner body, they may have an even
higher transfer rate than adult fish. And this is were they get there
required calcium.
It was mentioned that possibly Australian fish could get along with
less because they come from softer water. And yes they probably do
need less if you keep them in softer water. But we're not just talking
generally hardness here, we're talking TDS. And this means everything
dissolved in the water. In practice Australian fish seem to need the
same levels that New Guinea fish do. I have noticed that Psuedomugils
can get away with less, but not a whole lot less.
I really wish I had some hard numbers to pass on. But much of the
original testing occurred via unexpected failures. I knew my mix ratio
of tap to RO water so I could extrapolate and get reasonably close
numbers. I'd really like to set up some hard experiments and measure
all parameters very closely. Unfortunately that would require dumping
a number of species to make room and I'm not quite willing to do that.
But hopefully this will give folks an idea of what they are dealing
with. This theory also explains how fry can hatch in very soft native
waters and still not suffer from deformities. Of course those fry may
also have the advantage of a constant live micro food source providing
a degree of calcium, but that isn't a situation that can be duplicated
easily in a tank. And that's the place where we have to do our fry
raising.
later
Cary Hostrawser
My Rainbowfish Home Page
http://pw2.netcom.com/~caryho/home.html
Rainbowfish Study Group Web Page
http://home.stlnet.com/~gwlange/rainbowfish.index.html