Just an FYI - all tetracyclines are strongly inhibited by Ca and Mg in the water, they really should only be used in freshwater aquariums. They also react poorly to light, so shouldn't be used in a reef tank with full lighting.
Lewbart's dose for Enrofloxacin is a lot lower than 50 mg/gal (9.5 to 19 mg/gal). I presume Cipro is similar, as some fish metabolize enro into cipro.
Jay
I agree with the inhibition caused by Ca and Mg, however dosage rates in SW generally account for this (as with humans). Additionally, the UV degradation of doxy takes about 24 hrs, which is generally when it's time to dose again. That degradation is, in my opinion, an advantage over flouroquinalone treatment given the disposal of the water, post treatment. However, one could argue that factory farming's use of Cipro is far more damaging than that of reef hobbyists, but I digress.
While also a flouroquinalone, I'm not sure that Baytril would be my first go-to as an alternative to Cipro, despite its use in aquaria for decades. For note, Cipro is not usually my first treatment choice either, unless treating nems. This, in addition to the aforementioned lack of UV degradation, is also based on availability. In this case, for both spectrum and cost, I would likely substitute Neomycin.
Now, all that being said, you are undoubtedly the foremost authority on this, and I mean no disrespect at all. You have certainly forgotten more than I'll ever know, and that's for sure. My medical background just lends to a different approach.