6th March 2005 at 12:06 pm #617
That sounds like the reason. I have the thesis with me actually and I am slowly going through all of the oxygen diffusion graphs etc. It seems that increasing temperature allows more diffusion of oxygen into the water but that this is balanced out by (a) lower saturation of oxygen in the water at higher temperatures – I guess this means it disappears as easily, and (b) more biological activity due to the temperature that will end up using more oxygen to munch on things.
I am trying to figure out what that means for us in our environments where temperatures are 25-30 degs. It could be that we need to reduce the level of water to between 2 and 3cm according to one graph but I have to confirm. The reason they give for NOT doing that is one sentence – just that it will disturb the layer if water drips in and the level of water is too little….is that proven? It seems the shallower the water the better.
BTW sand filters may work here in Lumbala but the key will be affordability as there is not much of a cash economy and little alarm bells go off in my head when thinking about bartering for filters…..