The darn spores for those things are still likely in the tank. Maybe a diatom filter would reduce their numbers - if it was working.

Some time ago I quoted Diana Walstad's article where she used a diatom filter to remove as many free swimming Ich organisms as she could. In that case, cutting down the number of potential parasites while doing all of the other things one does to treat Ich finally enabled her to deal with a very resistant strain of Ich. Even the professorial types may have to struggle with these things sometimes.

I'm still doing battle with the Cyanobacteria in the living room 55. I covered 75% of the surface with Salvinia, hoping that it would shade the blue-green plague and out compete it for nutrients. That Salvinia doesn't grow as fast indoors as out, even with the light on 12-24 hours a day. (Sudden changes in environment may set aquarium plants back for a while - just as new house plants sometimes go through a slow period after significant changes.) After a serious water change, it came back some while we were away. (I told our fish sitter to feed live stuff when possible and blackworms produce a lot of waste. Walls of the tank were wiped off yesterday and a 40% water change was made, with the water slowly siphoning in during the world series.

I do wonder if I ought to try a CO2 dispenser which I won a while ago. Need to make sure that it is moderate in distribution so the fish are not bothered. That may be the limiting factor in plant growth there at the moment.

I also have a little Cyanobacteria in a somewhat neglected tank in the fishroom. I'll regard that as a warning to clean up that aquarium and be more consistent in terns of water changes. When one considered other ways nutrient rich water can manifest itself, I probably should consider myself lucky and be grateful that Cyanobacteria appeared rather than a bacterial infection on or in the fish..