I have a snowflake eel in my 60 gallon, the only other inhabit is a chocolate starfish currently. Okay so let me start from the beginning, I did a water change as normal, I did about 10 gallons out of the 60 and replaced it with clean new water. I added some buffer to raise my pH from an 8 to 8.1 and about an hour or two later I noticed my pincushion urchins spines were falling off, it was late and my local fish store was not available so I looked online and found that it was because of bad water quality. I then realized that I had used expired water conditioner so I bought a new conditioner at Walmart and immediately started replacing water. I replaced 12 gallons. Also , I had run out of my good conditioner which was why I used the expired one and later on realized, I hadn't been using this bad conditioner since this recent water change so the rest of the water should be ok. Anyways, I woke up the next morning to find my urchins spines all completely laying down, later on the starfish began to eat it and it is for sure dead. My starfish looks unaffected but my snowflake eel is losing coloring, I tried feeding him and he gladly took the food. What do I do???