Caulerpa

[spyderreef]

I am having trouble getting my grape caulerpa to grow again. It was doing great, I even took some in to the LFS and exchanged for some food. I've done some tests but everything is in the normal range.
I have test kits for alk., Ca, pH, iron, nitrate, nitrite, ammonia and phosphate. What else should I test for? Some of the hair roots turn red. The grape caulerpa simply does not grow then it turns a brownisn/white. I have a piece of red grape caulpera that seems fine. I also threw in some razor caulerpa and feather caulerpa. They are very small pieces that I found in my main tank.

 

[spyderreef]

1-55 watt Coral Life 50/50 PC
(50 Daylight 6000k, 50 Actinic 03 blue)
1-15 watt fl. that came with the tank
Lights are on 24/7
It is a 29 gal bow that is a refugium for a 125 gal tank. I have a mag7 that pumps the water into the 29 from the sump with an overflow box that goes back to the sump. I had great success first time around. I see a lot of what I think are amphipods. I put in two snails to help with some of the algae on the glass.
I moved some of the grape caulpera to my 120 and it seems to be surviving ok but it is still early. It is my second display tank and it is does not have much as far as corals in it. I am hoping to salvage enough to try again.
My 125 has hair algae that I never had before. Would a bigger water change help? I have an RO/DI unit with newer filters.
Can you grow caulerpa in its own tank or is it better as a refugium? I have a small ten gal that I was using as a hospital tank that I could do something with or is it too small?