I had been running a deep sand bed and recently changed it out for a shallow bed with coarser sand. My guess is the disruption this caused, including the rearranging of all the rock work, etc. precipitated this outbreak. Or it came in on some coral frags I acquired mid October at a frag swap weekend. I didn't add any of the water from the bags, but I didn't dip the coral either so it is possible that ich was present in some water droplets. I guess I got too complacent and lazy and fate stepped in to teach me a lesson. I saw one or two spots on them some weeks ago and kept telling myself it was nothing, then in the last week it became really clear. Only the two hippo tangs are showing symptoms, other fish (flame angel, mated clowns, chromis, kole tang, foxface) all seem fine. I know it's very possible they are affected too and just aren't showing the spots.
The Nu-clear filters seems to be larger and I can rig up a way to plumb it from an existing pump so I'm leaning that way. The model 533 is supposedly for tanks up to 90 gallons. Should I buy an extension making it 180 (makes the canister twice as tall and two filters) or run two in tandem. Or is just the one okay for this purpose? I'm not really clear on how much DE powder to use, nor how to actually use it with these filters. Hopefully someone can point me to some instructions.
Thanks guys.