Re: [APD] KH reference solution

[Thomas Barr <tcbiii at yahoo_com>]

> Second, weighting to 3 decimal places is impossible with
> normal hobby 
> equipment. A .1 scale will cost around $30-40, a .01 around
> $75-100 

No, they are cheaper than this:
http://search.ebay.com/search/search.dll?MfcISAPICommand=GetResult&ht=1&shortcut=0&from=R41&query=scale+0.01+gram&category0=

10-30$ Bubba:-)

and 
> a .001, who the hell wants to spend that much money. 

http://search.ebay.com/search/search.dll?sofocus=bs&sbrftog=1&from=R10&satitle=scale+0.001+gram&sacat=-1%26catref%3DC6&sargn=-1%26saslc%3D2&sadis=200&fpos=95616&ftrt=1&ftrv=1&saprclo=&saprchi=&fsop=1%26fsoo%3D1&coaction=compare&copagenum=1&coentrypage=search&fgtp=

I simply did a search for scale 0.001 gram on ebay and got many
hits.

The most of which is 40-55$
I'm not sure the accuracy, but it's not bad.
I have a much nicer 0.001 scale.
It only ran about 200$ but has a lot of nice features.
Then there's 0.0001 at work.
I can gauge the accuracy there of the other because it is
calibrated every month.

 In
> truth 
> though, if you have a descent, .1 accurate scale, or a balance
> you would 
> probably have enough accuracy.  As Tom said, larger volumes
> and amount 
> equals more accuracy, less error.  If you wanted to make 100ml
> of this 
> solution, you'll need a .001 scale but if you make 5liters,
> you should 
> be fine with a .1 scale.

Well  you can get another significant digit for a few $, see the
above link. 0.01 grams is fine for us in cost or accuracy etc.

10-20$ will get a scale that will do the job, then you can also
make calibration solutions to test other test kits etc or be
more accurate in your dosing if you are so inclined.
 
> That last, and maybe hardest part for most folks is measuring
> out 5 
> liters of DI water, or accurately measuring out any volume of
> water 
> larger than a few milliliters. 

No, most cooking cups have milliters, these are not that bad
really. When dealing with 5 liters anyway.

Using 500 milliliter volumes 10x is easy to do.
For dilutions, this is difficult.
But........ you can simple make more or buy some cheap pipettes,
cylinders etc from Aquatic Eco, they have lots of other items
folks can use. Chem supply places also.
 
> Yes, 
> making the solution from the standard kit is a crap shoot
> though there 
> is something to be said for consistancy.    As
> for an 
> accurate solution, I am just trying to share some ideas to
> make this 
> accessible/doable for more people.
> 
> Dennis Dietz

Makes 2 of us.
I think over all, the KH test kit can be replaced with a KH
reference solution. Is using a KH test kit "good enough"? For
many yes.

But........given the wide range of issues derived from variation
in the CO2 concentration(algae, stunted meristematic tips/roots
etc), I think moving to a KH reference solution is better than
using the KH test kit.

But unlike the making of the solution with a KH test kit, the
method I suggest is more accuraste and not hard at all either.

It also sets the stage for a much better calibration for other
test kits and measures for the hobby that aquarist can easily do
for about 20$.

I test water more than many, but it does not mean that other
like it nor do I as a routine.

Making a good size amount of KH solution to share and use is not
a bad idea.

CO2 is toxic to fish at higher levels and induces algae with
variation and low levels with hjigh light.

Given those two major issues, I think it's prudent to focus more
on these in an accurate and critical manner.

I think if you focus on fish health and are trying to maximize
the max CO2 with good fish health, this is a better method and
more accuracy will help you uncover what the range of max plant
growth and the upper ranges where you have fish issues are. 

This may all be done using a pH probe and the KH ref solution.
With the drop checker, given the errors involved with
colormeteric deterimination with the eyeballs, Vaughn is
correct, likely does not matter, but I'm still less trustful of
a cheap KH test kit.  

Regards, 
Tom Barr

www.BarrReport.com



 
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