Reef Chemistry Question of the Day #123 Party Effect on Aquariums

[Randy Holmes-Farley]

Reef Chemistry Question of the Day #123

Suppose that a reef aquarist living in New York City has a big New Year's Eve party. Dozens of folks crowd around his tank, admiring it. Just before midnight, he notices something unusual in his aquarium that was caused by the party goers, but everyone swears they didn't mess with the tank. What is the most likely thing that he observed?


A. The calcium level was 25 ppm higher than normal.
B. The alkalinity was 0.5 meq/L (1.4 dKH) lower than normal.
C. The pH was 0.3 pH units lower than normal.
D. The ORP was 25 mV lower than normal.

Good luck!






























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[jedimasterben]

The answer is C, because at parties people use up way too much oxygen and make too much CO2

 

[Up2no6ood]

The ph due to the elevated levels of carbon dioxide?

 

[Tabasco1]

The ph due to the elevated levels of carbon dioxide?

This

 

[JimWelsh]

The carbon dioxide affecting pH theory is the one that sprung to mind, and I'll go with "C", too, but for the record, this large a change (0.3 pH units) would require the ambient CO2 in the room to have increased by at least 500 PPM (easily doable in a crowded, inadequately ventilated room full of people drinking alcohol), *and* the aquarium water would have had to equalize sufficiently with the changed ambient room CO2 (far less likely). Still, I'll say "C".

 

[Pete polyp]

I answer E. Bill spilled his martini in the tank and it's having a bacterial bloom

 

[beaslbob]

C. Hot air of party ** lowered pH.

 

[beaslbob]

Wait a minute!
How much beer was consumed?

 

[glb]

The answer is C, because at parties people use up way too much oxygen and make too much CO2

Agreed. I know this problem very well.

 

[glb]

Wait a minute!
How much beer was consumed?

What exactly would happen if someone poured a beer into a tank. Just curious.

 

[Randy Holmes-Farley]

What exactly would happen if someone poured a beer into a tank. Just curious.

Happy fish?

 

[glb]

Happy fish?

And a happy foamy skimmer.

 

[reef life]

A shot in the dark! "D".

 

[beaslbob]

What exactly would happen if someone poured a beer into a tank. Just curious.

I wasn't actually worried about the beer being directly poured into the tank. :xd:

 

[nitro'sreef]

:crazy:

 

[Randy Holmes-Farley]

And the answer is...C. The pH was 0.3 pH units lower than normal.

The carbon dioxide in the air will rise in the room, reducing the pH. pH can easily drop a few tenths of a pH unit with lots of people around. 0.3 pH units is about a doubling of the CO2, which readily happens in a crowded room I blew into a skimmer once and you can easily see the effect on pH down stream of it. I also dropped a small piece of dry ice into my sump once as a test, and then got scared as the pH dropped (temporarily) well down into the 6's.

A reduction in pH will actually boost ORP.

Calcium and alkalinity will be essentially unchanged, although a drop in pH may cause a small reduction in the consumption rate for these, which might cause them to be a small bit above where they would normally be at that time of the day.