Generally there are few if any gasses (toxic) that need to be vented until significant amounts of anoxic conditions develop to produce the gasses. Anoxic often is at a minimum until the extended snow covered ice develops. It is my understanding that the primary "gasses" that need to be vented are methane and hydrogen sulfide, both not produced until anoxic conditions (anaerobic) develop and after the DO is exhausted.
Last edited by Bill Cody; 12/29/15 10:10 PM.
