Here we go again: MIs, Take III

[Samw]

Originally Posted by Aquattro

C'mon, you know what I mean. "Photosynthesis" as a cycle, so the respiration phase where organisms consume O2

And who turns off skimmers, that's silly.

I didn't. I thought you were literally asking about photosynthesis which is specifically producing o2 as a result. So you really meant to ask what is the effect of cellular respiration (the opposite of photosynthesis). So as I said previously, in my tank when I had algae and no UV, my levels bottom at 50% (sometimes less) and now with no algae and UV, my levels bottom at 80%. I read in research papers that some reef fish like some gobies can survive in 3% saturation and damsels and cardinalfish around 10%-20% saturation. It goes without saying that different species will have different levels of tolerance to hypoxia. All of my mysterious deaths of established fish as I can recollect seems to occur when my skimmer was off overnight and always angels so far (pretty sure the MI would have perished too if it hadn't been relocated prior). Since the skimmer is in my DT, I turn it off when I do water changes, feed the fish, etc.

http://www.fondriest.com/environment...n-chlorophyll/

"Oxygen Depletion and Fish Kills
If an algal bloom appears, a fish kill can occur shortly thereafter due to the environmental stresses caused by the bloom. A fish kill, also known as a fish die-off is when a large concentration of fish die. The most common cause of this event is lack of oxygen 45."