Help me ID this disease - ocellaris

[smokinstarfish]

Please help...
1.5" ocellaris clown, with a small oval-shaped white fluffy patch on side of body. It looks like a small patch of dried salt would. It's behaving normally.
I just bought one yellow tang, a bengaai cardinal, and two small ocellaris clowns, my only fish. The other fish seem fine and are acting normal. The tank's a 55 gallon that had been cycling with dead goldfish and some LR for five months prior, with a wet/dry bio ball filter. Ammonia and nitrites are 0, nitrates very low, temp 81, alkalinity is 10.
As for salinity, my Coralife Deep Six hydrometer says 1.020. That's low because the same hydrometer reads the LFSs water as 1.014, which I know truly is 1.023, so I figure my hydrometer's wrong, and I'm compensating. That would mean the water, if anything, is too salty. (I'm going to get it checked against a refractometer.)

 

[beth]

Could this be brooklynella? We resently had a thread here that had a pic of a perc with this disease. See if you can locate it and compare it to what you are seeing on your fish.

 

[smokinstarfish]

My fault… I've just sort of dropped the ball on this whole problem. So where I'm at now is both my ocellaris' are infected in quarantine. The original inflicted fish has become much riddled with these anomilies. Older patches have grown, the new ones being much smaller, and spreading outward from the original spot.
I'm unsure if this is brooklynella. It can’t possibly be ick. I'm more sure now that it is brooklynella than before, however. It fits some of it's symptoms but not all. It still looks white, raised off the skim spherical and small, crusty and crystally looking. There’s nothing trailing off them, coming from the gills, or slimy. Both fish are acting and eating fine. All the photographs on this board don't seem to depict quite exactly the same thing.
Ammonia 0, Nitrites 0 and Nitrates almost undetectable. RO water is used. Tank is getting past 6 months old now.
Another complication: The first sign of this is after I brought the fish home. They were the first SW fish I ever bought, along with the yellow tang and bengaai cardinal.
This was 14 days ago. I'm currently arguing with the LFS to take exchange them. They have no guarantee at all on marine fish! Wouldn't this still be their fault? Should they take them back? I couldn't have come from me, could it?
Also, what other things could this be than brooklynella? And with a value of these fish being a total of about $22US, is paying for treatment of anything worth it?
Thanks in advance everybody!