Looking at your first pics, it appears the size of your aeration boil is sufficient. I would consider relocating it to a more centralized location in the pond tho. Maybe even elevating it off the bottom to try to create a thermocline of deep cooler water.
I've seen that diffuser, but not familiar with its bubble production. You need a lot of tiny bubbles to create adequate lift of deeper water.
Surface of your pond is much cleaner than mine, and I'm running 12 hours at night, and still have a lot of phytoplankton scum on top. I took surface temp readings this morning and will be reducing run time for a later startup to let the surface cool more before it comes on.
Where are you taking your temp readings from? They should be from where your diffuser is currently located.
My diffuser is in the deepest part of the pond. A little over 10ft. Bringing it to a shallower spot may be a good idea to allow the deeper water not to mix and stay cooler.
Yesterday I took temp readings all over the pond at different depths and it was all the same temp or very close to it. It's obviously mixing all the water well. I keep my thermometer on one of my duck decoy strings. I can slide it up and down. This morning it was in 6ft of water on the bottom still reading the same as yesterday. About 83. I don't think I have a dying algae problem. With only 10in of visibility, I'm probably not getting much sun light penetration to get a good bloom. I think that gel I seen floating was just soil floc thats all over the bottom. Why it started floating yesterday with no aeration going, then was sunk again this morning after aerating last night, I have no clue. The more I read, the more I'm thinking its a DO problem exaggerated from the high temps. Hope running aeration just at night solves my problem.
