Bad day in the tank

newby30gallon

Just bought a coral beauty last week and had it in the QT. Woke up this morning to see dead coral beauty in QT tank. checked param's right away

PH 8.4
Amm 0ppl
N02/NO3 0 ppl
Cal >400
PHOS .5 ppl
KH 14

throughout the week i noticed that the KH was around 15-16 so i added zeph water to the QT which slowly brought it down to 14 . i assumed this would not be that bad and have seen it drop before in the main tank. i noticed yesterday that the beauty had a torn up back fin. i thought this was strange, although i assumed that i may have just missed it when i bought the beauty. if anyone can give a reason as to how this happened or just reaffirm that the KH killed the beauty.

also in the QT is two pieces live rock, bare bottom, powerhead, heater, and aqueon quiet flow 10, all in a 10 gallon.

kitten_penang

Scientific Name : Centropyge bispinosus Common Names : Two Spined Angelfish, Dusky Angelfish
Care Level : Moderate
Size : Up to 4 inches (10 cm)
Life span : 10 - 15 years or longer in the wild, but not likely in captivity
pH : 8.1 - 8.4
Temperature : 72°F - 80°F (22°C - 27°C)
Specific Gravity : 1.020 - 1.025
Carbonate Hardness (dKH) : 8 - 12°