I have an interesting problem in my tank. SPS (Acros and Montis) show very little polyp extension in my tank. If I put a hairy acro in my tank it will soon look like someone gave it a crewcut. The polyps are extended, but they are definitely not fully extended. The coral will continue to grow and shows no other signs of stress, it just won't fully extend the polyps. This is not just a single instance - it's been happening to me for years.
So, my question is - why?
Mixed reef - can toxins from the softies be affecting the SPS corals. Anybody out there with mixed reefs with similar experiences?
I used to have 400 watt Iwasaki 65k's, but just recently switched to 250 watt Giesseman 14.5's. No change in the problem.
All parameters that are easily measured are in tolerance. Since free phosphate is very hard to accurately measure, there is a chance that it might be problamatic; but I have no macro or hair algae in my tank, so I can't believe that can be the source.
That actually leads me to another question that may be an indicator - I have a very hard time growing any "healthy" algae in my tank or sump. I've introduced chaeto to my sump a few times, and it just languishes and slowly turns brown. It will live and grow, but just very slowly. I've always assumed I have little free iron in my system. Can lack of iron be a problem? Do hairys need iron supplementation?
This problem has persisted for years - it is not a sudden change. Anybody out there with a similar problem? Maybe we can compare notes.
Thanks in advance for any thoughts or advice,