Here is what I posted before about my battle with dino, this was back in 2016. -
http://www.bostonreefers.org/forums/index.php?threads/dinoflagellates.151731/
I had about a year long battle, tried gfo and it actually increased it. What I ended up doing is filter socks and change them every other day. I would do a water change sucking out as much as I could then go to an immediate lights out for 3 days, black the entire tank out so no light gets in. I used heavy duty trash bags, this also includes the sump if you have glass doors. I had to be careful as I have a gigantea so go extended lights out was something I preferred not to do, so I would do this once a month. I could see them fading but it was taking a while. I did this for months at end, I was getting ahead of them but slowly. At the end I was pretty much lights out for 3 days then on for two. That is what got me ahead of them from what I could see. I would still suck out as much as I could before lights out. I did have some recession do to the Dino's and also the lights out had caused some issues with other corals, my gigantea had shrunk. Since I've been feeding the anemone every other day or so and things are bouncing back. It's been about two months and I have not seen any Dino's in sight. I'm still going light on water changes right now until I know for sure that they are completely eradicated.
- Someone mentioned adding algea to a refugium that helped control his bryopsis outbreak-
Dino is nothing like bryopsis, they're called "the herpes of reefing" for a reason. The reason for the lights out is that dinos can strive in a nutrient poor tank and do the same in a high nutrient tank. No one really knows what they need to thrive other than light hence the lights out. Even at that it will take a while to get them in check and not sure if they will be completely eradicated.