Technically, anybody who used, or recommended, Bayer to dip corals is violating FIFRA because it is an off label use of the product so I would not recommend anybody use it--especially on a public forum.
Imagine a lot of the coral dips have what EPA would consider 25B ingredients, which are exempt from registration requirements. If not already registered as 25B they simply need to register, which is much cheaper than normal active ingredient registration. This is all those "all natural" insecticides with name your oil in it which, in reality do not really work. Actual organic pesticides like pyrethrum still go through the normal registration and maintenance process.
25B chemicals are analogous to the FDA GRAS chemicals on the food and drug side. Antibiotics fall under FDA so chemiclean would be under their purview. However, it's being used as a pesticide when controlling cyano so....
Also, if a company is already using an active that is already registered elsewhere, they still, at a minimum, need to register the label with the EPA--and this is must be renewed every year, or few years, can't remember. All this entails really is paying your fees--at least for the three labels I maintained for the DoD.