70 mph is legal on some roadways, while 30 mph is illegal in others.
There's a big difference between highways and city-streets - and terrestrial and aquatic sites; especially with chemistry half-lives, and from a long-term environmental impact perspective.
Will you own your pond forever? Will future owners of the property consider stocking it with fish, or use it to water livestock, or irrigate a garden - or for potable purposes as water-scarcity increases?
Black helicopters probably won't swoop in out of nowhere with camo-clad EPA officials aboard if you do something you really shouldn't. But, just because you don't get ticketed or cause an accident while speeding down a roadway doesn't mean it's safe to do so.
As for me, I definitely wouldn't use it in any pond under my control.
Zep: the "EPA waiver" in MS (and TX) was politically driven by commercial food-fish producers (it's called a Section 18 Emergency-Use Exemption) - and has no toxicological data to support such uses. Check the Sect-18 guidelines. 0.8 oz per acre-foot is the permitted dosage for controlling a specific form of algae that causes off-flavor in fish (but is insufficient for weed or filamentous algae control).
