Neat! About the red/brown spots... Well, I can't comment on mangroves specifically, but on plants in general, red/brown spots tend to happen when a) the lighting is too strong or b) there is not enough water. Now, in this case, water is hardly a problem, but the lighting may be the problem. That close to the plant, the light could very well be too strong, or at least too intense. You might want to try putting the lighting higher (maybe 5" or 6") for a week or two and see if that helps.
Another thing you should consider is that the spectrum is very different- both from the natural lighting they appear to have been growing under before and from the lighting that terrestrial plants normally receive. Terrestrial plants are adapted to grow best under warm-colored lighting with a lot of red, yellow, and green, which is what they get from the sun. (As an aside, seagrasses are not particularly fond of blue, purple, or UV, either.) This may be the reason that the leaves dropped off; the plants were not receiving enough useable light to sustain so many leaves. Or it could have just been some sort of shock from suddenly changing to a completely different spectrum. If it was just shock, then there isn't anything you can do, and it is over with by now anyways. On the other hand, you may want to shift your lighting towards the yellow end of the spectrum- either by decreasing the amount of blue and purple light or by increasing the amount of red light. Or you could add a warm-colored spotlight pointed towards the mangroves (nothing too intense, but something to shift the balance in that part of the tank without really changing the color of the light reaching the rest of the tank).
Nice zoas, by the way! I can't wait to see them grow all over the tree trunk!
Another thing you should consider is that the spectrum is very different- both from the natural lighting they appear to have been growing under before and from the lighting that terrestrial plants normally receive. Terrestrial plants are adapted to grow best under warm-colored lighting with a lot of red, yellow, and green, which is what they get from the sun. (As an aside, seagrasses are not particularly fond of blue, purple, or UV, either.) This may be the reason that the leaves dropped off; the plants were not receiving enough useable light to sustain so many leaves. Or it could have just been some sort of shock from suddenly changing to a completely different spectrum. If it was just shock, then there isn't anything you can do, and it is over with by now anyways. On the other hand, you may want to shift your lighting towards the yellow end of the spectrum- either by decreasing the amount of blue and purple light or by increasing the amount of red light. Or you could add a warm-colored spotlight pointed towards the mangroves (nothing too intense, but something to shift the balance in that part of the tank without really changing the color of the light reaching the rest of the tank).
Nice zoas, by the way! I can't wait to see them grow all over the tree trunk!
