A few months back, I began using Bio Pellets to improve the water quality in the tank, which in turn, would improve the coloration of the corals, specifically my SPS corals. The first few weeks went very well and the quality of the water improved dramatically, the coral colorations became vibrant, and they showed excellent polyp extensions. However, the next few weeks to follow were disastrous. I began to lose colonies of corals, one by one, as they would begin to STN (Slow Tissue Necrosis). I constantly monitored my water parameters, however, none were out of sort. I was frustrated, to say the least. A few weeks went by and I pretty much lost all my SPS colonies, however, the other corals (LPS, etc...) were doing well. I finally figured out the issue. The Bio Pellets did a phenomenal job cleaning up the water... in fact, too well. They had completely stripped my water of all nutrients that my SPS needed and they basically starved to death.
I've spent the next few weeks trying to get my tank back on track, which is why I haven't posted lately, as I was busy. Needless to say, I removed the Bio Pellet reactor from the system. Normally, I would just let the system bounce back on its own, slowly acquiring nutrients back from numerous feedings, fish detritus, etc... However, I don't have that option because I need to run a ULNS (Ultra Low Nutrient System) due to my heavy bio load of large tangs. I've done quite a bit of research and have decided to run the Fauna Marin Ultralith System.
On a side note, there was another issue with the tank. I had recently added an RBTA (Red Bubble Tip Anemone) to the tank. Unfortunately, my GBTA (Green Bubble Tip Anemone) had began to move and encountered the RBTA. They began to "fight" using chemical warfare and resulted in the death of both of them, as well as all the surrounding frilly mushrooms. They were all removed. Once the tank is back in pristine shape, I will add another RBTA.