Aw come on. I've managed to get outbreaks of the 5 major kinds in my systems (only one outbreak in my main tank, after that I just grew them in a test tank.)
That's no reason to surrender.
Gonna respond to your message here for benefit of whoever.
I said that these two kinds are typically non-toxic.
You said that your snails are falling over, and that you are adding pods and considering live phyto.
This is a problem, though Large Cell Amphidinium and Coolia are often low/no toxin, that isn't always true, and the snails are telling you there's toxins involved. adding pods or phyto in this context is simply adding organisms that will die due to dino toxins, and feed the bloom.
You may even need to move the snails if they stay lethargic, rather than letting dead snails fuel more dinos.