[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Aquatic Plants Digest V3 #338

Hi Firrest,

You mught be timid about stepping on some "giant's" toes, but you seem
to have grasped the essentials of water chemistry. Keep it up!

The "lather" statement refers to an old method of measuring water
hardness. One added a standard soap solution to a measured quantity of
water, shook it and if lather was visible on top of the water, that was
the end point. Now we use a color change to indicate the endpoint &
don't have to shake, just stir.


George S

> Subject: Re: Hardness Test Kits
> I am nervous about stepping in where giants tread, but something posted
> recently confused me a lot. And since Mr. Booth is off the list for awhile,
> maybe someone could help clarify this for me.
> Mr. Booth posted:
> >Well, it's not rocket science. First one must buy the LaMotte Hardness test
> >kit model PHT-CM-DR. Using a simple titration technique, one first determines
> >the "Total Hardness" (their term) which is Ca+Mg. This test has a resolution
> >of 4 PPM.  Then, using different reagents in the same test kit, one
> determines
> >Calcium hardness (same resolution). By subtracting calcium hardness from
> total
> >hardness, you have now determined magnesium hardness.
> Mr. Pushack posted:
> >Ah HA! so you admit then that the Dupla test kit is NOT in fact a GH
> >test kit but actually a _Calcium_ test kit and a "total hardness" test
> >kit in disguise (whatever the heck THAT is). Is that permanent total
> >hardness or total temporary hardness? AND since its a Dupla test kit,
> >then aren't the units therefore in German degrees? What is the
> >conversion factor from German to American degrees? 9/5 + 32??  ?;->
> >From Mr. Booths web page, it seems clear that GH is Ca + Mg concentration, so
> I don't quite see what the problem is - the LaMotte kit (a very nice one I
> might add) measures Ca+Mg or just Ca allowing you to calculate Mg.  Mr.
> Pushack seems to have become very confused with the different nomenclatures
> for hardness. And what does a Dupla test kit have to do with anything at all?
> And the 9/5+32 is a temperature conversion.
> It looks to me like I changed information sources just in the nick of time.
> >And now I suppose you are going to tell us that potassium has nothing to
> >do with hardness and therefore we should not be concerned about
> >measuring it?
> My impression was that potassium has nothing to do with GH or KH. Also, I
> remember that it is difficult to measure and most people depend on a proper
> trace element mix (Dupla or PMDD) to insure they have enough.
> >I guess since potassium and sodium do not affect our
> >ability to generate a lather, then they don't figure into the equation?
> OK, I'm confused by this statement.
> Forrest King
> Checking  Mr. Booth's WebPage for things I missed the first time
> http://www.cco.caltech.edu/~aquaria/AquaticConcepts/