I haven't measured alkalinity in that pond but I will. Most of our ponds are also primarily groundwater ponds and run around 100 mg/l.
We had a feeder set up feeding aquamax 500 to the shiners / perch the summer of 2015 but it had a problem. The shiner population really took off that summer. We didn't replace the feeder this past year, but would could this season. The pond has lots of chara (our local nutrient hog), so getting a decent bloom might be tuff. Maybe we'll focus on getting small feed going early in the year. What are your thoughts on timing to start feed?