Forget about having a pond that you treat like a swimming pool, ain't gonna happen. The pond itself is the bio filter. Greenish tinted water (phytoplankton), weeds in the pond, Redear Sunfish to control snails which is part of the life cycle of swimmers itch, etc. Have an area that is cleared for a beach, and let plants grow in the rest of the pond. The plants will utilize nutrients that would otherwise get plentiful enough to create a toxic blue-green algae bloom over time, once the nutrients build up enough in the pond.

The only other way to do a swimming pond would be to have a wetland area that is the same volume as the pond, water wise, and have it filled with plants. Pump water in one end of the wetland and have it trickle out the other end to the pond. Put fatheads or Gambusia in the plant filled part of the pond, and some Redear Sunfish in both areas.

Here is some reading for you:
https://www.goodhousekeeping.com/home/gardening/g1146/natural-swimming-pools/?slide=4

www.hoosierpondpros.com


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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).