Which Alk Hanna checker?

DracoKat · Jul 17, 2016

I am confused.. there's two hanna checkers for Alk.. not sure which one to get?

DKH or PPM? What is the difference between these two?

twilliard · Jul 17, 2016

The difference is how they display the value to you
One takes a multiplication of .056 and the other requires no calculator
I use the PPM and over time you don't even need to do the math.
For instance my tank sits right around 164

DracoKat · Jul 17, 2016

which one doesn't require calculator?

twilliard · Jul 17, 2016

DracoKat said:
which one doesn't require calculator?

The DKh

Eckolancer · Jul 17, 2016

Dkh I think is a new one. The ppm one just uses a conversion to tell you what dkh your result is at.

DracoKat · Jul 17, 2016

thank you! now I know which one to order

Randy Holmes-Farley · Jul 17, 2016

IMO, neither ppm not dKH are good units for alk (meq/L is the standard for scientists), but reefer history has many folks stuck in a ppm or dKH world.

FL_Reefer · Jul 17, 2016

Randy Holmes-Farley said:
IMO, neither ppm not dKH are good units for alk (meq/L is the standard for scientists), but reefer history has many folks stuck in a ppm or dKH world.

Can you expand on this please? What do you recommend? hanna makes it very easy to test and keep stable for me

Randy Holmes-Farley · Jul 17, 2016

It is the units I rail against, not the device.

As I mentioned, the preferred units for scientists are meq/l (milliequivalents per liter). Those have a perfectly understandable meaning to any scientist in the world.

OTOH, the actual meaning of dKH or ppm calcium carbonate equivalents is lost on 99.9% of reefers, and might have little meaning to many scientists (especially dKH).

twilliard · Jul 17, 2016

Randy Holmes-Farley said:
It is the units I rail against, not the device.

As I mentioned, the preferred units for scientists are meq/l (milliequivalents per liter). Those have a perfectly understandable meaning to any scientist in the world.

OTOH, the actual meaning of dKH or ppm calcium carbonate equivalents is lost on 99.9% of reefers, and might have little meaning to many scientists (especially dKH).

But to the standard home aquarist dKH is a standard is it not?

Randy Holmes-Farley · Jul 17, 2016

twilliard said:
But to the standard home aquarist dKH is a standard is it not?

For reefing, yes, but only because most kit makers force it so. If they used other units, reefers would too.

fab · Jul 17, 2016

Randy Holmes-Farley said:
IMO, neither ppm not dKH are good units for alk (meq/L is the standard for scientists), but reefer history has many folks stuck in a ppm or dKH world.

What is the conversion for ppm to meq/L?
And for dKH to meq/L?

Randy Holmes-Farley · Jul 18, 2016

fab said:
What is the conversion for ppm to meq/L?
And for dKH to meq/L?

The Units of Measure of Reefkeeping by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2005-08/rhf/index.php

from it:

Alkalinity is a measure of the amount of acid necessary to reduce water's pH to the point where all carbonate and bicarbonate have been converted into carbonic acid (about pH 4.2 in seawater). In seawater, bicarbonate and carbonate provide nearly all of the alkalinity. Consequently, reef aquarists can use it as a surrogate measure for bicarbonate and carbonate which are taken up by calcifying organisms (Figure 1). The units of alkalinity can be meq/L (milliequivalents per liter), dKH (degrees of carbonate hardness), or ppm (meaning ppm of calcium carbonate equivalents). One meq/L = 2.8 dKH = 50 ppm CaCO3 equivalents. Seawater has an alkalinity of about 2.5 meq/L = 7 dKH = 125 ppm CaCO3 equivalents.

Sharvey103 · Jul 21, 2016

Randy is absolutely correct. As a degreed chemist meq/l is preferred.

RobBaglieri · Aug 10, 2016

Randy Holmes-Farley said:
IMO, neither ppm not dKH are good units for alk (meq/L is the standard for scientists), but reefer history has many folks stuck in a ppm or dKH world.

coming from a chemistry background dKH means nothing to me. meq/l makes more sense. Never really studie the term alkalinity in school. Im used to buffers, buffering capacity, pH, pKa... where did this dKH come from?

Randy Holmes-Farley · Aug 11, 2016

RobBaglieri said:
coming from a chemistry background dKH means nothing to me. meq/l makes more sense. Never really studie the term alkalinity in school. Im used to buffers, buffering capacity, pH, pKa... where did this dKH come from?

Old German term for degrees of carbonate hardness, used by water people and aquarium people there in the past.

Keen4 · Mar 23, 2020

RobBaglieri said:
coming from a chemistry background dKH means nothing to me. meq/l makes more sense. Never really studie the term alkalinity in school. Im used to buffers, buffering capacity, pH, pKa... where did this dKH come from?

europe?