Wow, all that stuff is really expensive.
Yep and it looks like you have a lot to treat. How large are your two ponds?
Another thing that can make algae worse is very gradual shallow shorelines. Shallow gradual sloping shorelines are great for wading and safety concerns but can really encourage algae growth. That's one reason you don't see as much algae out on the middle.
I wish my shorelines were a but more drop-off type that would discourage algae growth. It would be expensive for me to try and go back after the fact and make my shoreline more steep.