Macro algae dying...Why?

I would try running the lights in a 12 hour cycle, preferably when the DT lights are off. My forte isn't phtosynthetic organisms, but my understanding is that photosynthesis still needs a "rest period". It is also possible that the nutrients needed to grow the algae just aren't there (based ont he fact that you don't have any algaes growing in the DT either); namely phosphates and nitrates as I understand it - I suppose very frequent water changes could have a similar effect. This isn't necessarily a bad thing as the reason we add macro to our tanks is to keep the aforementioned levels in check. I imagine you are not using a phosphate remover and/or doing and sort of carbon (aka vodka) dosing? The only other thing I can think of is your flow. How fast is your flow going through the fuge area? Super fast or super slow will produce equal problems. Are your plumbing the entirity of the DT overflow directly through the fuge? Just a portion? Feeding the fuge with a separate pumps? Lastly, I know hermits like to eat up chaeto especially, at least in my experience and in some others' who I have talked to. I am not sure that pods even feed on the chaeto itself directly, so I don't think you have to worry about them. Either way, I have TONS of pods and they don't seem to put a dent into my chaeto growth.

 

i would try changing your light to a 6500k daylight spiral bulb, i get mine at wally world. and get a clamp on reflector from there also or ant hardware store. some people are using the compact flood lights.