I am trying to bind phosphate in drinking water ponds. In my area we have small 1/3acre -1/2 acre ponds. I am seeing extremely high phosphate levels with the labs classifying them as hypereutrophic. This seems to be a leading cause to algae problems that have been hard to get under control (lyngbea and cyanobacteria). With the history of our area, there are more instances of this issue each year. I need an effective game plan.

Here is an example of a pond I struggled with last year. I decided to spring for lab testing and use this as a test pond for future reference.

Given 1/3 acre and 14ft deep drinking water and recreational pond with adequate Aquashade season long.
5/12 Algae Treatment- 2.5gal Cutrine Plus
6/3 Algae Treatment - 2.5gal Cutrine Plus
7/8 Algae Treatment- 150Lbs Phycomycin + 7g Captain XTR + Adjuvant
7/10 Nutrient Binder- 2qts EutroSorb WC
7/21 Algae Treatment- 5g Captain XTR
8/2 Water LabTest - Free Reactive Phosphate 5.1 ug/L, Total Phosphate 51.2 ug/L
8/2 Algae Lab Test- Heavy presence of Leptolyngbya, Coccomyxa (Chlorophyta); Cosmarium (Streptophyta), much bacteria observed
8/18 Prescribed Algae Treatment - 150lbs Phycomycin + 5g Captain XTR
8/19 Prescribed Nutrient Binder- 2qts EutroSorb WC + 100# EutroSorb G
9/1 Algae Treatment- 5g Captain XTR - 150lbs Phycomycin + 30lbs Cutrine Plus G3.7%
9/9 Algae Treatment - 5g Algymycin
9/13 Algae Treatment - 5g EarthTec
9/19 Water Lab Test- Free Reactive Phosphate 5.0 ug/L, Total Phosphate 120.2 ug/L
9/19 Algae Lab Test-Oocystis, : Scenedesmus (Chlorophyta); Aphanocapsa (Cyanophyta), some bacteria observed
10/18 Nutrient Binder- 100# Aluminum Sulphate + 50# EutrSorb G

While I could knock it back, I was never able to get the algae under complete control. The opinion was that until the nutrient levels get under control, I won't have algae control. It was also explained that there is phosphate in the water table, but also phosphate in the sediment that gets re-released (due to algae growth on the rocks).

With the given information above, would you have a recommendation for treatment (s) this season?

Thanks for your time and help!!