Hey Guys. I had bought a yellow tang and 1 1/2 weeks later it died. Brought a water sample to my lfs and they said the alkalinity was low and that could have killed him. I didnt know that so now ive been keeping the alkalinity up. I bought another yellow tang and it also died about 1 1/2 weeks later. This one was alot more active and would pick at the rock all day and swim around. The first one didnt. I thought he was good. I tested the water and everything was good. Any ideas why?