I had a big problem with losing alot of acans and micros about a year ago, I racked my brain for over a year and lost thousands$ in LPS. I never found the exact cause but found several things that im sure one of them was the problem.
1. And most likely - I always used Instant Oceans ALk test kit. It was crap and was nowhere near right. Several other locals were using the same one and all of them read wrong. I was running way low on my ALK. I now use a troic marin test kit and have had no issues since, stuff is growing great.
2. I found a 4ft long ucnid worm in the tank. It is amazing that after 6 years of being in the tank I never once saw him.(120gallon) He was as big around as my thumb and 4ft long when stretched out. He has been residing with a friend who wanted to keep him as a pet. He says he has to feed it Zooanthids. (funny i could never keep zooanthids!) Anyway, not likely you have that problem as ive only read a couple places online where people have found large ucnid worms in tanks.
3. All my problems started with my first addtion of 7 aussi acans. Alot of people seem to think that Aussie stuff brings bugs that cause recession. Some have claimed Interceptor treatments cure this problem. I did not dose interceptor.
None of this may apply but figured i would share just incase!
Good luck
