Natural pool with waterfall to promote water flow through plants. And I think i would add hidden fencing or chicken wire to make a koi pond inside the planted area. The koi are cool, but the also add the nitrates to the water to feed the plants!
Eco-Friendly Natural Swimming Pools Natural pools eliminate harsh chemicals like chlorine by combining the cleaning properties of plants with bio-filtration and skimming systems. The pools are separated into two zones the plant zone and the swimming zone.