I think that perhaps in some ways Cary and I are saying the same thing. My
theory is that the KH, i.e. sodium carbonate absolute levels (and possibly
other buffering components) were producing some sort of adverse effects on the
fry. Carbonates also produce ions and are considered part of the total
dissolved solids. I just say this in passing to those that might not be
familiar with the terminology. The total dissolved solids would include not
only the general hardness part of the equation (magnesium and calcium), the KH
part of the equation (carbonates) but also the "salty" part of the equation,
like sulfates, chlorides (table salt), potassium chloride. (what else are we
forgetting Dr. Craig?). I suppose that other ions could also make a
difference. I'll have to take a look at what my water company says is also in
my water as I don't have any easy/reliable methods to define anything beyond
Ca/Mg and carbonates. If I remember it was fairly low.
Cary would you agree then it would be quite simple for me to perform the
following experiment to see if I could produce deformed fry if it is just a TDS
effect.
1) take my tap water which grows fry quite nicely (if I don't doctor it with
any baking soda) and use it in one tank.
2) Take a second tank and add just sodium chloride (table salt, not sea salts)
to it. I want to add an amount that will be equal in TDS to the amount of
sodium bicarbonate that I would add to a third tank. What I think I want to do
here (Craig??) is add the same micro-molar amount to each tank. Both should ?
dissociate fairly completely and give close to the same micro-semen reading if
I have done my math correctly. A 2 millimolar solution of sodium bicarb would
be 168 mg per liter (based on a MW of 84). A 2 millimolar solution of table
salt would be 116 mg per liter (based on a MW of 58.44). If I haven't
forgotten anything here these two solutions made up in the same tap water
should read the same with the meter. Their total dissolved solid content would
be the same. The general hardness would remain the same as no magnesium or
calcium is being added. However the KH or carbonate hardness would be pushed
essentially through the roof! Since all hardness measurements revolve around a
1 mMolar (100 mg/liter based on a MW of 100) solution of CaCarbonate std (100
ppm) a 2 mMolar solution of baking soda would be a 200 ppm increase in KH or 11
degrees (17.9 ppm =1 degree hardness). I might have to halve the total
dissolved solids depending on how much table salt per gallon that actually ends
up but I would still suggest that even an increase of 5.5 degrees KH would be
enough to produce damaged fins in my water. I felt I was seeing it with only
an increase of 2 degrees KH.
Assuming that the meter reads these two solutions as being the same Cary would
you agree that they would then have the same TDS and should therefore both
produce equal amounts of "definned" fry? I think from your suggestions of TDS
that you would feel that it would. If on the other hand it is only a KH ion
addition that produces the problem then I would suggest that we'll see
"definned fry" only in the bicarb tank and not in the tank with the table salt.
I think for a first try this would be a simple experiment to try, I feel that
the results will be rather dramatic.
* Naturally we'll have to check to make sure we aren't producing any pH
extremes in these two tanks. A large difference in pH would certainly cause
concerns. A repeat using all tanks buffered with something like Trizma might
be a good second experiment if the pH's are quite different. A third
experiment would be to compare my tap water to the salted tank and a third tank
that has only magnesium chloride added at the same TDS as the salted tank.
I think that either way the implications are if you have fairly hard water AND
perhaps a high KH that you should get the proper kits to check your total
calcium levels. The water differences in the US are very extreme so if we can
define this problem then we'll know how or when we'll need to solve it. And
Bruce's comments about Ron Bowman's observations. I used to believe that
"little stream theory" until I saw that when the only change I made was adding
bicarb I got fin deformities. I never took any stock in the bitty animucule
:-) ladened with calcium theories, they are just too far out of bounds,
especially when you consider that they also get live foods in tanks and still
<can> get deformities. An "unbalanced ion" theory is a much simpler theory
that also helps to explain why some people have deformities and others never
see it, all based on their water makeup. Any comments??
Gary Lange
gwlange at STLNET.com
Rainbowfish Study Group of North America
http://home.stlnet.com/~gwlange/rainbowfish.index.html