I do think it may have been due to bio-load. I got behind on PWC
's on this new tank, and had a lot of purple algae (?). I've started changing ~ 20% every weekend. Tank has all the LR
it has room for - don't know total weight, as we bought in small batches over time, but probably > 2lb/gal
. Most of the LR
(all Fiji) came out of the old 36-gal
tank. The sand was new, but when I set up a transition tank (30-gal
plastic tub) I seeded the new sand with bundles of live CC from old tank, tossed in a couple of shrimp bits, and cycled it. Other fish are 6" speckled green puffer (eats a lot), 4" yellow tang, 3" zebra damsel. I think I'd been overfeeding too, and have cut back. I'll try to check water parameters again tonight. Don't have a QT tank now.