>
><snip>
>> 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 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
>
I think your test would certainly be valid and give us more
information than we presently have. There's always the possibility
that will create even more questions, but it would be nice to nail
down exactly what is happening. Is it your theory that an imbalance in
ions creates a condition making the calcium less available? I do know
my straight tap water GH 17 degrees, KH 15 degrees, pH 9.5, does not
give me any problem with fin deformities in fry. But it some cases, I
can't even get eggs in that water. That is why I cut it with RO water
and drop the pH with phosphoric acid (30% RO, pH to 7.5 typically). I
think this is really the opposite effect of your addition of sodium
bicardonate. And either condition creates deformed fry. We still have
the imbalance of ions, but my imbalance has decreased and not
increased. Granted my calcium level has also been cut by 30% but my
ion imbalance has been reduced by a factor of 100. It may be all part
of a more complex problem. If your experiment shows a difference I
think the next question would be, are unbalanced ions making the
calcium unusable to the fry or changing the permeability of the fry?
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