Hey all, I just got rid of these guys for the third time in my tank. I'll share my observations and how I dealt with them.
First time I had them was about five years ago when I started getting into corals. At the time people were treating dinoflagellates with hydrogen peroxide and nutrient removers like gfo, so I tried that as well. In the end, I didn't get rid of them. I found a nicer, larger tank that I upgraded to and started over. First tank had undetectable po4 and around 30 nitrates.
In my new tank I've had it twice. First time it happened I tried nutrient control and hydrogen peroxide. Those did nothing, even with heavy gravel vacs, siphoning, bubble scrubbing, blackouts. At the time I was running carbon, a skimmer, and vodka dosing. My nitrates were elevated in the 40ppm range but my phosphates were always zero. So after many unsuccessful attempts to get rid of it I went with the "dirty method". Against all common coral keeping advice, I stopped vodka dosing, removed the carbon, turned off the skimmer for half the day and took my gfo offline. It took a few weeks, but day by day they went away until the tank was perfect again.
Second time was a few months back. Tank looked great and perimeters were fine, been using an algae scrubber to much success, but my phosphates were "high" at about .1 ppm. Wanting to get more into sps, I added gfo to bring it down. Within about a week or so the dinos were back. Once again, I removed the carbon, took my scrubber offline (it was completely engulfed in dinos at this point), took out the gfo, and let the tank go. All i did was make sure it was aerated and had good circulation. Once again they disappeared over a period of about three weeks.
Here's what I took away from my experiences:
- Gfo was the common denominator. Every time I used it I ended up driving my phosphates too low, which I believe is what is causing the blooms. From what I've read on these forums in the past couple years the vast majority of reefers are getting dino blooms when their phosphates hit zero (or close to). From the older reefers I hear that Dinos were not very prevalent years back, probably because they didn't have the capability to reduce nutrients to as low of levels as we do.
- Amphidinium doesn't seem to be super toxic. I had no large scale die offs in my tanks.
- UV did nothing for these, I used it every time I had them. It's possible it does kill them but there's too many in the sandbeds to kill them all. I was using it in my sump, I couldn't tell you if putting it in the display would help.
- Gravel vacs and siphoning helped, but I don't feel its super important when trying to get rid of them. They would be back in full force then next day when I did it. The last time I had a dino bloom I barely did any siphoning, they just slowly dwindled down to nothing as time went on.
- Blackouts do nothing. They always come back within a couple days.
- I did dose waterglass to raise silicates and try to out compete them with diatoms. While I did notice some nice sponge and diatom growth (especially on the glass) I can't say for certain if it actually helped reduce the dinos. Sorry.
- Raising ph did nothing. I had my tank heavily aerated and dosed with kalk to keep ph up to around 8.6 to 8.7 at times and it didn't both them.
- H2o2 did nothing against this species whatsoever. Obviously other people have had luck with it so it still may be a viable tool.
- Around the time the dinos were being defeated the glass and sump started growing green algae again. I do have some hair algae growing on some rocks but my clean up crew munches it down quickly.
- Ordering pods and dosing phytoplankton, in my experience, did nothing. The pod population did explode to insane levels though (looked like swarms of flies in my fuge), which was pretty fun.
- Adding straight up 'biodiversity' did nothing. I ordered garfs gunk and tried getting nice pieces of live rock full of goodies when I went to local fish stores. The creepy crawlies I got were cool but it didn't do anything for slowing the dinos.
- Bacterial additives did nothing for me, including Vibrant.
- No medications helped, including Dino X.
- Water changes neither reduced nor created more dinos.
As of today my tank is sparkling clean from dinoflagellates. I am no longer trying to keep my nutrients at ultra low levels, all it has caused me is headaches. All I use for filtration is an algae scrubber (which works incredibly well) and my skimmer part time. I'm not using carbon at this time as I see no real reason to. I'll most likely never use GFO again. I know many reefers use is it effectively, it's just not something I want to deal with again. My nitrates are sitting at around 15 ppm and phosphates are just over .1ppm and all my corals are quite happy. Hope this helps someone fight this scourge!
