Low /high water column..more/less O2 ??

[MickeM]

Hi all !!

What about this thought..??

....A low water column (without any currents!!)- more O2 ??!!, easier for O2 to reach the bottom ??( Compared to a higher water column??)..

or is this a myth??
Since less currents probably prevent the CO2 to reach the surface and escaping from the water into the air in a more rapid way?? , but...Maybe also lead to less help for the O2 at the surface to reach the bottom??

All this is of course dependant on other factors as well !! (Amount of Detritus/restproducts, water chemistry in the specific water volume +macro/micro biological situation at the specific locality!!/ in the tank..)

/Micke

 

[gerald]

True, if you have a heavy bio-load (lots of decaying organic matter) and no current. But it takes very little current to mix the tank from top-to-bottom; just a small trickle from an airstone will do it. So in practice you're not likely to have a low-oxygen problem in a deep aquarium, with a moderate fish load and typical aquarium filter or aeration.

 

[MickeM]

I thought so.. That is my experience..

How about a tank with no filter/pump at all..?? only a tank with a bottom of "biological" sand/gravel..or only peat ??
In the killifish hobby a lot of people keep breeding-tanks with no artificial oxygenating at all, but very controlled water changes+feeding pattern.. ( 1pair of fishes+plants+snails)

I have gotten really good Apisto+Killi results with that set-up + no/ almost no currents at all..
The main issue is probably the amount and quality of food !!

This will result in one new specific thread about snails!!

 

[gerald]

I dont think any general statement about this will be useful. Whether the bottom layer of water has sufficient oxygen for fish and eggs to survive will depend on too many variable factors, and can change from day-to-day depending on temperature, plant photosynthesis, rate of organic matter decay and bacterial respiration, thermal convection currents (from a heater or sunlight through a window), and the fishes' activity. For killies, the bottom-spawning species typically have eggs that are adapted for low-oxygen conditions. I would guess that most cichlid eggs and newborn fry probably need more oxygen. Killies can swim immediately after hatching to find water with more available oxygen; cichlids can't.