Looking at the temp profile from 7-26, the trout only have <2' of water to live in without at the bottom of the pond that is below 70°F, and we have no idea what the O2 levels are down there. Just because the water is <70°F doesn't mean that there is enough O2 for them to survive. I have had trout stay alive in 80°F water that had aeration and a surface agitator running. So if enough O2 is available it might be possible for them to stay alive all year long in your pond.
There is an O2 system on the market that will put O2 into water below the thermocline and not disrupt the thermocline. But you'd better be sitting down when you see the price of it.
Very good point! Only 2' of water is below 70 def F, and that is localized to the deepest hole in the pond, which is not that big around. Yes, I have no idea what the DO is at the moment.
I recall seeing that O2 system advertised somewhere. Big bucks.
OK, I will stick with aeration, and plan on a trout harvest/die off by next summer. In addition to the diffused bottom aeration, I do have a fountain that the previous owners left behind (and wifey likes it). It can provide a little bit of supplemental surface agitation that the trout may appreciate.
