My 29 Gallon JBJ Nanocube is about 3 weeks old now. I started it with live rock from an established tank, and everything looked great. Ammonia 0, Nitrites 0, Nitrates very close to zero. Put in a couple of clownfish -- hungry and doing great.
Then at the ARC sale I picked up some Xenia and a couple of snails. The Xenia disintegrated almost immediately, and the snails never moved after I put them in the tank. 24 hours later, still no movement no I assumed they were dead. Puzzling. I thought maybe I just had some bad snails, and Xenia is always a toss-up.
Somehow I decided to question my salinity. Checking the water from ARC and another ARC person, both of their water samples were 1.030. That couldn't be right.
I had been using a refractometer, and it said the water was 1.024. Perfect. I bought a cheap swing-arm and checked. 1.010. What? Did some more checking and realized I had calibrated my refractometer incorrectly. I had used a calibration solution at 53 mS but was looking at the wrong units on the refractometer. My water was actually 1.010. A this point, I figured it was better to bring it up quickly than slowly (no real corals to worry about). Over the process of about 6 hours I brought it up to 1.020, low but tolerable. No problems with the fish. Amazingly, the fish seemed to not care about the salinity (or swing in salinity at all).
Let that sit for a couple of days to stabilize and the tank params were all good. Put in some snails from Aquatek today and they went to town immediately.