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Re: [APD] KH reference solution


Thanks for the links.  When I was shopping around a while back for my 
scale, I could not find a descent digital above .01 for less than ~$75.  
Believe me, if I had I would not be stuck with a .1 scale.  Maybe its 
time to upgrade... wait, I'd rather eat for a week:)

Tom said,  "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."

I don't agree with this.  If we are worried about weighing dried powder to .001 or .0001 we certainly need more accuracy than a Walmart measuring cup and measuring 500ml 10 times.  That is 10 times the chance for inaccuracy multiplied by the assumption that the the cheap Chinese knockoff cup is correct.  Plus, which side of the line do we measure to.  Making a .001 measurement and then measuring the water that way is like jogging while smoking.  There is no point, IMO.


  Thomas Barr wrote:
>> 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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