They positively will destroy SPS! and while use of a turkey baster may not be a good idea when they're only on the walls or equipment, once they are on your colonies I advocate that you baste your balls off, and try to save your prized SPS specimens.
Having recently won the battle against dinos myself I can say for sure that that is not always the case! There are a number of different types of dinoflagellates, luckily they do respond to a number of common treatments.
The best, first and foremost, is not doing water changes. Especially if you have been using any sort of carbon dosing, and you've really managed to drive your nitrates down, they will exploit this environment, and furthermore feed off of the trace elements (inorganic or organic IDK but) in the new salt water you introduce. Also stop the use of any AA's is probably a good idea.
Skim wet, and replace GAC every other day (this was a turning point for me)
The black out scenario helps kill them off by reducing their access to light, of course your animals like light too. Once dinos are growing on them, the light will pretty much be useless to your SPS. I think however 4 or 5 days is a little drastic IMO. I did two 48 hour blackouts over the course of 3 weeks.
Some dinos don't respond to higher pH seemingly at all (mine didn't) and it is very difficult to maintain especially when your dripping kalk into a small system, you can end up lowering your salinity in a matter of a couple of days, and then what do you do? a water change? Wrong!
It took me only 3 weeks to beat them, and things are recovering quite well at this point. It is difficult, good luck to you.
-Andy