A 'swimming pond' as presently understood in the industry has everything that a normal constructed pond would have minus fish, and includes a 'regeneration area' which is basically a heavily planted constructed wetland. This regeneration area, to be effective, must equal at least 40% of the entire swimming pond surface area. In other words, if the swim pond is 20' x 20' (400 sq/ft) 160 sq/ft minimum of this area must be set aside for regeneration.
Search 'Bio Nova'. They are presently the leading company in this field.
"Everybody is ignorant, only on different subjects." - Will Rogers