Re: [Killietalk] What's in my water

[Barry Cooper <bjc3 at centurytel_net>]

Answering Ken and Wright:

Ken, that's true, a simple calculation should predict the right mix, but 
confirming it by testing a small mix might be useful. My approach was 
more complex than needed.

Wright, it is true that many pumps exchange ions rather than simply pump 
a single ion. One very important one is the Na:K ATPase, which is found 
at the cell membrane of every cell. It exchanges Na ions for K, keeping 
Na high outside the cell and low inside, and the reverse for K. It 
exchanges 3 Na for 2 K. It is essential for cells to be able to maintain 
osmotic balance. All cells contain a lot of protein, which exerts and 
oncotic (i.e. an osmotic force). To balance that tendency to draw water 
into the cell, Na is maintained at a high concentration outside the 
cell, via the Na:K ATPase. Furthermore, the same pump is used to set up 
conditions that lead to the polarization of excitable cells, such as 
muscle cells, nerve cells, heart muscle, etc. There are other mechanisms 
that require exchange too, one example of which is the sodium:calcium 
exchanger in the heart, where calcium levels, which control the force of 
contraction of heart muscle, are regulated by exchanging for sodium ions 
from outside the cell. Presumably that mechanism operates in fish heart 
muscle, although I don't know that for sure.

So, at least in theory, lack of other ions like K & Ca could lead to 
diverse forms of cellular dysfunction. I apologize to those of you who 
didn't want the biology lecture.

Barry

Barry J. Cooper
Sweet Home, OR 97386



Ken Simolo wrote:

>Having done both, it is much easier and MUCH less costly to remove 
>hardness from hard water using an RO system than to increase hardness 
>to soft water by adding Equilibrium, etc.  If you only have a tank or 
>two, it does not matter much but if you have a lot of tanks, 
>Equilibrium becomes expensive.
>
>For all the reasons that Barry mentions, I use tap water to 
>recondition my RO water.  However, I do not think you need to do all 
>of the testing Barry mentions.  If you know what is in your tap water 
>already (amount of hardness, alkalinity, etc.), then you can 
>calculate how much you want to dilute it with RO water.  As a general 
>rule, for breeding fish, only hardness is important.  For keeping the 
>tank from crashing, you do want some alkalinity (buffering capacity).
>
>ken
>
>
>  
>
>> People say it is easier to add hardness to soft water than to 
>>remove it from hard water. It IS easier, but I'm not sure it's as 
>>effective.
>>    
>>
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