Reef Chemistry Puzzle #6

[Randy Holmes-Farley Verified Community Expert]

Reef Chemistry Puzzle #6​

Two clues today...

1. In nearly every reef tank, I rise and fall in a daily cycle.

2. My units of measure are given relative to something else.

What am I?

Good luck!



Previous Reef Chemistry Puzzle:

https://www.reef2reef.com/threads/reef-chemitry-puzzle-5.1019608/



























.

 

[mues]

Alk!

 

[ScottJ]

pH

 

[Fish Styx]

Ph. It fluctuates daily and is actually a measure of free hydrogen.

 

[Court_Appointed_Hypeman]

PH is my first guess, but PH isn't really a measure of something else is it? Power of hydrogen is still basically just measuring hydrogen no? Or perhaps the fact that it is not at all a measure of quantity or concentration of the element that it is in fact a measurement of something else. I guess the something else it is a measurement of is voltage from hydrogen ions, which I guess PH doesn't technically stand for.

I am going to go with PH for my answer, but the second hint makes me unconfident in this answer. If it is correct to say PH is not a unit that describes voltage from hydrogen ions then I think I am wrong, but electrical activity of hydrogen does sound a lot like, "power of hydrogen"

 

[Alexraptor]

Definitely pH, alk not likely since in a closed system it can only fall, and not rise, without outside intervention.

 

[Mr_Knightley]

PH.

 

[rhitee93]

Yeah, pH was my first thought too, but I don't see how it fits the 2nd clue very well. It is a direct measurement of hydrogen ions.

What about ORP? That's more of an indirect indicator.

 

[Reefer911]

pH.

Potential of hydrogen.

 

[Court_Appointed_Hypeman]

pH.

Potential of hydrogen.

Oh christ, I thought it was power of hydrogen all my life lol. I'm a dummy.

 

[twentyleagues]

ph

 

[Randy Holmes-Farley Verified Community Expert]

Here’s a clue about a clue: clue #2 alone might be sufficient to pick out the answer I intend.

In other words, what things that we ponder can only be described with units of measure that are relative to something else?

FWIW, I explicitly explain this in one of my articles. :)

 

[Fish Styx]

Here’s a clue about a clue: clue #2 alone might be sufficient to pick out the answer I intend.

In other words, what things that we ponder can only be described with units of measure that are relative to something else?

Well, we Americans will measure things in anything but the metric system. So, no help there. I mean, I live a four iron from 7-11 and that's about two football fields.

 

[Randy Holmes-Farley Verified Community Expert]

Here’s an example of what I mean by a unit of measure that must be relative to something else: altitude in meters. Saying your altitude is 457 meters says nothing without knowing relative to what? In this case, it is likely mean sea level.

 

[Troylee]

Ph level.. co2 saturation.. I’m getting a headache :face-with-tears-of-joy:

 

[Fish Styx]

Light intensity via PAR?

 

[AKReefing]

Reef Chemistry Puzzle #6​

Two clues today...

1. In nearly every reef tank, I rise and fall in a daily cycle.

2. My units of measure are given relative to something else.

What am I?

Good luck!



Previous Reef Chemistry Puzzle:

https://www.reef2reef.com/threads/reef-chemitry-puzzle-5.1019608/



























.

pH

 

[jda]

If it is pH for the measurement, then the relative is co2.

It could also be carbonate which fluctuates in small amounts with light cycle consumption and people measure it in alkalinity.

co2 was the answer to chemistry question #2, so probably not a repeat?

 

[mues]

Here’s a clue about a clue: clue #2 alone might be sufficient to pick out the answer I intend.

In other words, what things that we ponder can only be described with units of measure that are relative to something else?

FWIW, I explicitly explain this in one of my articles. :)

Salinity? varies if you don't have an ATO, even though generally in small amounts... salinity is only relative salt to water

 

[dennis romano]

pH where the concentration of hydrogen atoms must equal the concentration of hydroxide atoms to get a pH of 7. Acids have more hydrogen ions therefore <7 pH. More hydroxide ions means a higher pH.