Evaporation

PeaBrain · Apr 18, 2020

When the water in our tanks evaporate, which molecules dissipate and which are left behind? In other words, is there anything besides H2O that goes with it?

Copingwithpods · Apr 18, 2020

From evaporation just h2o, why?

Crabs McJones · Apr 18, 2020

Water only, salt, elements, and minerals stay behind

PeaBrain · Apr 18, 2020

Copingwithpods said:
From evaporation just h2o, why?

A YouTube video featuring a noteworthy reefer was asked about water changes, and this person said they didn't do water changes, and left it up to evaporation. Just didn't sound right to me.

Copingwithpods · Apr 18, 2020

PeaBrain said:
A YouTube video featuring a noteworthy reefer was asked about water changes, and this person said they didn't do water changes, and left it up to evaporation. Just didn't sound right to me.

Hmm yeah that definitely sounds off, like mentioned above the only thing that leaves ours tanks through evaporation is h2o everything else left behind, got a link to the video I'd love to hear the context.

PeaBrain · Apr 18, 2020

I don't think she knew really what she was saying, but it was enough for me to want to clarify. 6:50 mark.

Copingwithpods · Apr 18, 2020

Lol OK so yeah she's couldn't be more wrong. Evaporation does not count as a water change. We do water changes to reduce no3/po4 which don't evaporate, dilute toxins which don't evaporate and replace trace elements. About the only thing about that which could be seen as a true water change is that she frags alot, so she is removing alot of saltwater from her tank daily and replacing that with fresh saltwater which is indeed like a little daily water change. But the evaporation part, yeah she's coo coo.

There are tons more wrong with her statements too, yikes. You can even hear it in the guy's voice "yeah I guess you could" he was being very nice and respectful and didn't call her out on it although I'm sure he wanted to.

Randy Holmes-Farley · Apr 19, 2020

There are some things that come off by evaporation besides water. The simple fact that you can typically smell the water proves that. Mostly these will be small organic molecules (like dimethyl sulfide, part of the "ocean" smell when at the actual ocean), but may also include some inorganic ones such as ammonia or hydrogen sulfide.

Copingwithpods · Apr 19, 2020

Randy Holmes-Farley said:
There are some things that come off by evaporation besides water. The simple fact that you can typically smell the water proves that. Mostly these will be small organic molecules (like dimethyl sulfide, part of the "ocean" smell when at the actual ocean), but may also include some inorganic ones such as ammonia or hydrogen sulfide.

Sure some bacterial off gasing and some other particles are present in evaporation in miniscule quantities but to say that evaporation alone is enough of a water change as in evaporation alone will keep up with waste production or toxin accumulation is a ridiculous claim and one I hope people don't take as gospel. Soon will be hearing "all my corals are dying I haven't done a water change in a year because my tank evaporates so much water, I saw it on youtube".

Randy Holmes-Farley · Apr 19, 2020

Copingwithpods said:
Sure some bacterial off gasing and some other particles are present in evaporation in miniscule quantities but to say that evaporation alone is enough of a water change as in evaporation alone will keep up with waste production or toxin accumulation is a ridiculous claim and one I hope people don't take as gospel. Soon will be hearing "all my corals are dying I haven't done a water change in a year because my tank evaporates so much water, I saw it on youtube".

I certainly was not suggesting it had any relevance to a water change.

Randy Holmes-Farley · Apr 19, 2020

Here is one of my reef chemistry questions of the day about this very topic:

Reef Chemistry Question of the Day #260 Loss of Elements by Evaporation

Which of the following elements (in any form) is least likely to leave a normal reef aquarium by evaporation from the top of the water? A. Hydrogen B. Sulfur C. Nitrogen D. Potassium E. Oxygen F. Iodine G. Bromine H. Carbon Good luck! .

www.reef2reef.com

from it:

Which of the following elements (in any form) is least likely to leave a normal reef aquarium by evaporation from the top of the water?

A. Hydrogen
B. Sulfur
C. Nitrogen
D. Potassium
E. Oxygen
F. Iodine
G. Bromine
H. Carbon

Good luck!