Sorry for the long post.
I moved an established nano tank that I purchased last week. The drive was 2 hours with about 30 minutes of prep work before the move and 45 minutes of setup post move. So the whole process took just shy of 3 and a half hours.
The tank is a 12 gallon nano cube with the following contents:
1 Royal Gramma
1 Red Firefish
1 scarlet hermit crab
4 various snails
10 pounds of live rock (allegedly) It now has 11 pounds after I added about 5 pounds of hitchhiker free live rock from my LFS.
1 emerald crab (new addition) - saw a little bit of hair algae and had these guys recommended for me.
1 green unknown soft coral (I believe it was/is a ricordea - an addition from me)
I know nothing about this particular system other than that it was allegedly running for like 6 months and that it has a ton of coralline algae.
I was told the salinity was 1.024 and that there was no ammonia, nitrite or nitrate in the tank and the PH was 8.4. I took it home and set it up and had my LFS test the water the next day. No ammonia, nitrite or nitrate but the PH was 7.8. I bought a cheap salinity tester (deep six) and the water tested at 1.29...
Topped off the tank with RO water and the salinity dropped to 1.28. Primed the deep six for 24 hours with salt water to ensure accurate readings. The next day salinity read 1.29... brought another water sample to my LFS and he used a hydrometer to read the water at 1.38! In addition the nitrite read 1.0.
The fish appear to be doing fine as are the mushrooms and the toadstool. I haven't seen the emerald crab since I put him in but the hermit crab seems fine. I am pretty sure I lost the ricordea (it turned brown).
I purchased pre-made water and plan on draining the tank down to the sand and filling it up with the pre-made water to correct PH and nitrite issue (will acclimate the 2 fish and the crabs/snails with an extended slow drip.
Now my questions:
1) What could have caused such a spike in salinity? Logically I can't think of anything other than the previous owner having a broken or not properly calibrated hydrometer.
2) What could have caused the nitrite spike? Nothing that I was able to see died and there was certainly no over feeding issues.
3) What is the coral in the attached picture and is it salvageable?
4) Am I taking the proper approach in draining the tank and filling it with known good water?
Also... are the little brown things in the front... are these star polyps or something else? I have dozens of these on a couple of rocks.