Quote:
Originally Posted by gobytron
The fishes you have reported dying have extreme sensitivity.
not sure if you read that right (or I typed it right).
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Yup. that's what I said. The fish that are dying are extremely sensitive. But the conditions are not extreme. For example (i'm making these numbers up of course) most fish can survive under 50% DO saturation. Because most fish can survive at 50% saturation, this level is not considered extremely low. However MI and dwarf angels can not. So they are extremely sensitive. I made those numbers up to illustrate my point of course. I would have to measure the DO to know exactly at what point the MI starts to suffocate while all other fish do not. But it is probably at some level that most people do not think their tank is low on DO. DO fluctuates wildly depending on many factors. I've measured 40% before in my old system with airstone skimmer on with no deaths. My old system went as high as 130% during supersaturation by photosynthesis. With my current system, the lowest it'll get is 80% and the max is 98%. I'm sure that when I experienced the deaths overnight with aeration off, DO was well below 40%.