Laser light will penetrate fine in clear water. Focusing is variable and done with a low power targeting laser affixed to the primary laser. The targeting laser also identifies any potentially hazardous reflections prior to firing the primary laser.
I'm not sure what is meant by your term "enhanced Palytoxin". While I've not been able to locate much research on this use, existing research indicates heat does destroy Palytoxin. I don't beleive there would be an increase in toxin release compared to any other in-tank eradication method, perhaps even less. The laser focuses light energy up to 100,000 times, thus the 1800mW laser being utilized is is the equivalent of up to ~180,000 watts of energy being delivered to the focus point. I suspect that potentially toxic compounds would be quickly broken down by the localized intense heat