I just did a large water change in what had been my sorority tank. My girls have been dropping like flies and I'm down to 2 from a high of 10 I was beginning to think that something had been sprayed outside that drifted through the window and poisoned them but for the fact that the RCS appear to be fine. Anyway, when I poured the new water in it kicked up a bit of murk from the sand. It was very fine dust and didn't stay long but after I noticed that it had caught in mucusy stuff trailing off my plants and driftwood making them look like dusty cobwebs in a haunted house. Has anyone seen this before or have any idea what caused it? Could it be related to the deaths of my Bettas?