Oxygen demand is highest during the night and the lowest level is at dawn, which is when most fish kills occur. The increase in algae is coming from an influx of nutrients, i.e., uneaten food and fish waste. When you added the dye to the water you may reduce the algal population slightly, but you also decrease oxygen production significantly. A good rule of thumb is feed no more than the fish can eat in 5 minutes. Feeding will drop off as the water temperature drops.
F stop feeding.
This a more long term problem. My advice is to fish the pond hard before next summer. We have installed an auto feeder, and an aerator. Playing at this has been fun and we've begun to harvest some by fishing. At this point they are about 14 inches long and probably weigh about a pound average, this after about 8 months.