I've been sucking it out into a sock. Spend about an hour or more trying to suck it all off the sand and rocks. Within two days, it will grow back to the same amount that was previously sucked out.
Looks like I might be losing my tono wrasse. I spotted it swimming funny just right now and doing barrel rolls. I just netted it and put it in an acclimation box. I hope it pulls through but I doubt it. In past experience, once a wrasse starts swimming funny, it's a goner. It's either the dinos or possibly swim bladder affecting the wrasse.
Here is a post from sonnus explaining why trying to filter dinos with filter socks doesn't work:
http://www.socalireefs.com/forums/s...t-dinoflagellates/page2&highlight=dino+sonnus
There are posts on reef2reef about dosing hydrogen peroxide and having really good success and it appears some what reef safe. I haven't done it myself though.
If you can't get it under control and it continues to get worse do a full blackout for 3 days, where you cover the glass of the tank. I use black plastic trash bags and tape them up. Minimize ambient light in the room if possible, skim heavy and run fresh carbon to pull toxins from the water. Siphon as much out as possible before you start. I've done this on a few different tanks and it works well. It knocks it back completely and allows other algae like your macros to take over. Just be sure to turn that fuge light off as well during the blackout. Feed less if at all during that time to try and minimize nutrient spikes as it dies off and stops consuming everything. Dinos grow so fast my nutrient levels have always read 0/undetectable when its present in the tank. Ease back into your lighting cycle over a day. If you do a water change and its getting worse silicates might not be getting removed by your RO/DI water, or mixed salt?
I've done this in tanks that have sps, lps and inverts. I've lost 2 pieces of sps one time but i didnt do a great job siphoning before the black out and beleive i had a nutrient spike. I will say i never really had to battle dinos in my 100g and for whatever reason that system consistently ran around 8.6 pH, probably from my oversized skimmer. So that route may work as well.
Best of luck. It can be very frustrating.