Gas Exchange?

  • We are currently upgrading MFK. thanks! -neo
T

Tongue33

Feeder Fish
MFK Member
Feb 11, 2006
8,060
16
0
48
Utah
www.davescichlids.com
Ok so I am quite frustrated.. I have been searching and reading as I am now reallizing that I am not educated on Oxygen, and gas exchange..

Plus I am wondering is actually needed and where?

I have not found any real content in the reading I've done here.. And elsewhere didn't satisfy me, due to the fact that I only trust a couple sites for certain info. And haven't even heard of the ones I was reading on..

So can some one explain to me the process and where I can put my air?? (Options) My spray bar creates enough surface aggitation across my tank. Running a mag 24, pushing around 1600-1850 gph through a 1" x 72" pvc .

Let me see if I can get a pic of the top of my tank.. I know I have one on this site.. So hold up on the replies :) Thanks

Ok This is a little bit of what the whole surface of the tank looks like...It is actually rougfher than this.. But this was taken last month :)
attachment.php


So can someone please tell me the process and why and where the o2 is necessary? Please don't reply if you only have time to keep it simple.. i want to know the ins and outs.. and if you know of some literature that would help that would be nice too :)

I understand that most believe bubbles and such to be useless but I want to know why :)
 
from what I know as an enviro tech in training...I'm no scientist but a few factors have been explained to me,
- temperature - colder the water the more 02 dissolves in it,
- surface area - the amount of h2o directly touching the surface (bubbles, wave ripples, how wide or deep your tank is)
- how ventilated your hood is, it is good to get it completely covered but it's good to get some fresh air flow over the surface they use oxygen too so thats a stuffy glass box to begin with.
-you said you had air going into it, putting a plant or rocks over the air will keep air bubbles under the surface when some collect under a leaf or something, also the bubbles get bounced around, broken etc so this helps mix it up again, also once again surface area water/air
-live plants good
-fish/water ratio
along similar lines, many people in winter months when the house is sealed up most of the time that it's low oxygen, headaches, low energy. probably too subtle of a difference to affect the fish, but ya never know:drool:
 
THanks !! THat is insightful... Maybe not exactly what I wanted to hear :) But I don't really know that what i wanterd to hear is what I needed. And that defenitely helped with some new knowledge period :)

Infact I don't even know what I wanted or expected so that was very helpful thanks again :)
 
gas exchange is not exactly rocket science but it may be more complicated than is necessary depending on what your goals are.

The more details you can give the easier it would be to decide if you should run any numbers or not.

In the mean time heres somethings to consider
--------------------------------------------------------------------

as stated before the overall gas transfer rate is influenced by temperature, the area of the interface between the atmosphere and the liquid, pressure (read elevation), saturation concentrations, etc etc etc. Gas transfer is constant (not the rate, I mean it is always happening, even at equilibrium, your aquarium will not technically ever be at equilibrium because your fish are using the dissolved oxygen in the water)

the relationship between the equilibrium concentrations of gas dissolved in solution and the partial pressure of gas is defined by Henry's Law

http://www.google.com/search?hl=en&q=Henry's+Law&btnG=Google+Search

atmospheric pressure at sea level = 14.7 atm


henry's constant for air in 1 x10^-4 atm

0 degrees celsius 4.32
10 degrees C 5.49
20 degrees C 6.64
30 degrees C 7.71
40 degrees C 8.70

for Oxygen

0----2.55
10---3.27
20---4.01
30---4.75
40---5.35

air is approx 20.9% oxygen

at 70 degrees f = 21 degrees C dissolved oxygen in fresh water at atmosphereic pressure and oxygen saturation of air = 20.9% dissolved oxygen = 9.17 mg/L


---------------------------------------------------------------

Ill scan some material and post it this evening if you are interested
 
I am not clear what you want to know.

The heavier the bio load the more likely there could be a lack of O2 and excess CO2.

The typical way to manage this is with a gas exchange tower or setup...... a tall bio ball tower with alot of splashing and plenty of fresh air will keep the O2 at the max level and reduce any build up of CO2 and N2.

You dont need to add O2 directly
O3 ( ozone ) is added for sterilization like UV.

Also the tank needs plenty of circulation to bring water from the bottom to the top and also thru the gas exchange tower..............

Hach sells an O2 test kit if you want to measure the O2 saturation

I hope this helps...........If not what is it that you are trying to figure out..??
 
also what I have done since my tank is "getting there" to it's capacity is bought a filter intake extension to suck up water from the bottom and put it on top, what happens at times is the water based on where the filter is, how strong the current is and plant set up, water pools in areas which leads to cold water spots/warm, calm spots what help breeding for hydras and white spot, which isn't bad but can be annoying, but generally oxygen saturation isn't a big deal with tanks, i've seen oxygen tablets but that's more for moving fish and practical jokes
 
Well I believe all this info has greatly helped me :) And completely answered my question.

THanks guys.. But also sprung a new question as the last response..\

Can I move my air bars to my sump and be ok.? MY tank is 33" tall... And my sump has a nice drop through the scrubbies befor hitting the sump water level.. So I'm cool with the tower right??

If I am understandin correctly then this is an option:)
 
You must log in or register to reply here.
MonsterFishKeepers.com
Top Bottom