Reef Chemistry Puzzle #8

[Miami Reef]

HI! I asked Randy if I can do today’s Reef Chemistry Puzzle. He generously said yes!

Reef Chemistry Puzzle #8

Two clues today...

1. Loads of things want to consume me in a reef tank.

2. I’m pretty shy. Not even a TDS meter can detect me…but it can if you put me in freshwater at a pH of 7.

What am I?

Good luck! ;)

Previous Reef Chemistry Puzzle:

https://www.reef2reef.com/threads/reef-chemistry-puzzle-7.1021725/

 

[Reefkeepers Archive]

Some sort of trace element....

 

[Reefkeepers Archive]

Not iron as i can test for that...

 

[Reefkeepers Archive]

Not iodine....

 

[Reefkeepers Archive]

Strontium?

 

[Dbichler]

I’m terrible with these but my guess would be phosphates

 

[Blopple]

Ehhh, H+?

 

[Randy Holmes-Farley Verified Community Expert]

Nice puzzle!

I have my possible answer in mind. :)

 

[Raul-7]

Amino acids?

 

[Reefering1]

Carbon

 

[DCR]

Ammonia

 

[bushdoc]

TDS meter works on principle of measuring conductivity, so it cannot be any "mineral".
I suspect it's something in gas or liquid form.
Ammonia in typical Reef Tank is mostly in liquid form, but in neutral pH it would be ionized ammonium kation and it would be detected by TDS meter.
Bacteria and corals consume ammonia, so this is my guess.

 

[shakacuz]

ammonia?

 

[JonoH]

Its alkaline right?
Ph of 7 is neutral, anything lower is Acidic, anything above is alkaline?

 

[Raul-7]

It might be NH3/NH4+, but even at pH 8.3 both exist. So a TDS meter would be able to detect it.

In fact, only once you get past pH 9.3 does it favor NH3.

 

[bushdoc]

^^^I agree with your reasoning, but big part of my professional life is answering various test questions and the closest answer is the right one, so I still opt for Ammonia.

 

[Rp8]

Ammonia

 

[Miami Reef]

@jda @MnFish1

Any guesses? :)

 

[Randy Holmes-Farley Verified Community Expert]

It might be NH3/NH4+, but even at pH 8.3 both exist. So a TDS meter would be able to detect it.

In fact, only once you get past pH 9.3 does it favor NH3.

I hope Miami doesn’t mind me giving a hint on his puzzle, but here goes…he did not say it was undetectable by tds in a reef tank. :)

 

[Miami Reef]

I hope Miami doesn’t mind me giving a hint on his puzzle, but here goes…he did not say it was undetectable by tds in a reef tank. :)

Thank you, Randy. I don’t mind at all. :)