Since your water temperatures are low, I think you drowned your roots even with the air stones because you went from soil to water.

You don't need to change the height of the plant in the net pot, just change the height of the water. The roots won't dry out, that's how roots work and they will take the air they are accustomed to getting in your soil environment from the air above the water line in this case.

The water should be as low as you find efficient. Thats another thread. In the meantime just keep the water level somewhere in the middle of the bucket.

Next, why are you using ph Up and Down? And don't buy into using H2O2 for extra oxygen. It's not a slow release capsule, it burns off very quickly.

And finally, if you built your own aerocloner than you need a filter. That is the spec on those spray/mist heads. That aside, you should dip your shoot into the cloning gel or solution, and the only thing you should fill the rez of your cloner with is water with a B-1 solution. How is the gel clogging your nozzles?