The tank was cloudy yesterday and I couldn't figure out why. I'd done a normal water change on it the day before and thought maybe I'd overfed. I also noticed that white crap was back on the underside of the wood too. I did water tests and they looked normal, so I pulled the prefilter, cleaned the sponges and put it all back together with a packet of purigen. I put the purigen in, not for the cloudiness, but because I was tired of the slight tannins still leaking from the wood. I cleaned as much of the mulm up as I could, trimmed the Vallisneria and cleaned and trimmed the flame moss. Started everything back up and checked on it a few hours later. The cloudiness seemed to be less, but this morning it looked crystal clear. I'll water test again at lunch. With the small group of rummy nose and xrays it's continual motion in the tank.... It's so fun to watch.