Coralline Question - Can you help?

[jpc763]

So I have had my DT up since July. I have had some, but really minimal coralline growth. My water levels have been very good since my cycle completed.
I have had my QT up for a month. I put a fish into the QT and began monitoring it. I noticed that there was a lot of coralline growth. Well after 1 month, there is noticable coralline growth on the bottom, back and pumps. The rocks that are in there are turning a deep purple. There is clearly good coralline growth.
Now I started up the QT with water from my DT. I use the same water, salt, etc. The DT has T5 lighting and the QT has CF.
Any idea why there is great grwoth in the QT and minimal growth in the DT?

 

[b bauer]

are they both glass tanks or is one acrylic? my tank grew it on all the plastic parts first.

 

[fishfanny79]

You really need to check the levels of Calcium and Alkalinity.
Something that jumped out at me...why is there live rock in your QT?

 

[jpc763]

My DT is glass. My QT is acrylic.
I have a few pieces of LR in my QT to help with the biological filtration. I dosed the tank with the rock in it so now it is permanent.

Thanks. John