I can't figure out what the hell is happening in my tank. Today, I very suddenly lost a purple firefish and three blue/green chromis. The corals looks great though.
Tank has been up and running for 125 days today, all params are spot on. The firefish suffered from fin rot from first being introduced around thanksgiving and never really fully recovered but the chromis have me stumped. At first I thought oxygen levels in the tank were low because two of the chromis kept hanging out at the surface. We're in northeast PA and got slammed with that blizzard so the house has certainly been shut up tight the past couple days. Between the return and the skimmer, there's plenty of surface agitation and should be enough gas exchange. I opened the windows for a bit just in case.
Other than that, the only thing I can think of is my tendency to overfeed or some type of infection. I don't QT (I know I should, and I'm very likely going to after this) but inspecting the dead bodies, I didn't see any glaring signs of ich or fungus or anything out of the ordinary, other than on the firefish. That still was showing fin rot symptoms (tail gone, white spots on its one pectoral fin).
As for the overfeeding, after blowing off the rocks and shallow sand bed for the water change today, the water column is filthy. I'm going to not feed for a few days and see if I can salvage the rest of my pets, but I'm not terribly optimistic I'll see anything swimming by morning. Any thoughts or suggestions? This very much sucks. I feel like I've done everything right, but clearly I went wrong somewhere.
Specs:
55 gallon with 20g sump
55 lbs live rock
3/4" aragonite sand bed
reef octopus 150int skimmer
two koralia 2 powerheads on a wavemaker controller
reefbreeder photon 48
spectrapure refurb RO/DI
instant ocean salt mix
Inhabitants:
Two purple firefish (minus one now deceased)
Six blue/green chromis (minus three now deceased), introduced to DT 10 days ago, no QT
1 Yellow watchman goby
1 pistol shrimp
8 trochus snails
2 astraea snails
6 nassarius snails
6 cerith snails
4 nerite snails
green mushroom coral frag
candy cane coral frag
pipe organ coral frag
Food
Fishyfood from LFS (blender mush)
mysis shrimp
brine shrimp
Frequency: alternating daily
Params
Sal: 1.026sg
pH: 8.02 currently
temp: 79.8F
Using red sea test kit
NH3: 0
NO2: 0
NO3: 2
dKH: 9
Using salifert test kits
Ca: 405
Mg: 1210
Maintenance
Weekly 10% water change
Monthly 20% water change
Dosed calcium for the first time yesterday using Randy Holmes-Farley recipe #1 (prestone driveway heat calcium chloride - 1 cup dissolved in 1 gallon ro/di water) - dosed 8 oz to bring up Ca to 420 from 380
