Our tank: 100 gallon live rock/live sand reef tank. 7 fish. 3 shrimp. 2 starfish. 30ish snails. 25ish hermit crabs. A multitude of stomatella. 15ish corals. Equipment: 2 wavemaker-controlled powerheads Strong return pump (at work, exact specs at home) Protein skimmer 40 gallon sump with 3 sections baffled off (refugium in center) PO4 reactor All chemical specs are fine. Nitrates are at zero, obviously nitrites and ammonia are also at zero. Alk is higher, calcium is high, and the only problem is a slightly low pH of 8.0 which I'll be buffering up tonight. I'm assuming it's dinoflagellates as it looks exactly like this (not my tank): However, I read this article, which under the heading "Dinoflagellates in the Aquarium: "Snotty" Dinoflagellates and Fish Parasites" says that it probably isn't, in fact, dinoflagellates and is more likely chrysophytes. In any case, has anyone else had this particular problem? It's bloomed all over my substrate, liverock, and is even seeming to "attack" my hammer coral (it's not brown jelly, I've dealt with that before). Thus far, my plan is to remove my snails to a quarantine tank, as I've heard dino affect them more than the other creatures in the tank. I did a 24 hour blackout last night, and it seems to have slowed it down. But my coral provider said that just slows their metabolism and to keep the lights on regularly, otherwise efforts to kill it will work less effectively. He told me to raise my pH to 8.4-8.5 and keep my Alk high. Any other suggestions? I've also heard to avoid doing water changes as to starve it of nutrients. Good idea/bad idea? Anyone ever successfully eliminate this stuff? Did you have any casualties in the tank? Thanks!