For example, pond specific 'healthy bacteria' $300

(I'm picking random examples off google, no endorsement or past experience here..)

http://www.newtechbio.com/catalog/index....6b2c0fa3b764035

vs..

plumbers stock bacteria, $10 for 5 gallons.


https://www.plumbersstock.com/product/43...0YXL5c9bt_D_BwE