High light levels killing coralline algae

LockeOak

New member
Much of the LR I put in my 10G nano had quite a bit of purple coralline on it, also some green coralline. Under my cycling light setup (13W PC and a 60W incandescent) it did fine, under the permanent setup (130W 50/50 10K/actinic PC) it's dying off. I can confirm that it is the high light levels and not low alkalinity or Ca (alk is decent at 7.5kH and calc is unknown), as a long piece of horizontal tonga rock was half shaded by a big ball of chaeto. After about 3 weeks, the purple coralline on all the rocks as well as on my turbos' shells is turning gray and dying off, after moving the chaeto to the fuge the once-shaded coralline is beginning to die as well. It's not really a problem, I'd rather it die off than cover my glass, but I'm glad that I figured it out and it's not a water problem. The green coralline is doing ok, which is fine by me because it's a really cool color (almost fluorescent!) and doesn't seem to grow in plates. Just an observation to help anyone else wondering why their LR is now covered in gray spots.
 

plyle02

Active member
Probably has to do with the PH, Alk, Calcium relationship. Have you been testing? I mean the basics, that will let you know quite a bit. Also, what type of water is going into this tank? If tap, I would add a RO/DI filter, and that will be a good start. Just my opinion though...
 

LockeOak

New member
pH is a bit low (7.9-8.0), I'm experimenting with my kalkwasser additions to keep it up and stable. alk is a steady 7.5kH. I don't have any calcium tests yet, but no corals except for 10 zoanthid polyps so nothing to really be harmed there. The water is RO/DI from the biology lab where I work. Again, I don't really mind that it's dying (I don't like it on the glass), but I thought my observations might help others.
 

plyle02

Active member
I would have to say in my experience that you are probably low on calcium. Your alk seems a bit low, maybe the addition of a 2 part system, and Salifert testing of both Alk and Calcium will help to get you balanced.
 

conefree

Gene Pool Lifeguard
Another possibility is the large change in lighting. Certain types of coralline do well under certain intensities of light. You will more than likely see it die back for a while and then come back after the adjustment.
 

redox

New member
coraline grows like crazy in my greenhouse. so light is not your problem. I agree with the other people who say you should check parmeters. I have platelets of coaline (all different colors) growing on everything. I can put a piece of pvc in the water and within3 weeks you cant tell it apart from a piece thats been in there for months:D conefree hit the nail on the head.
 

kmf507

New member
It is true that a change to brighter lighting will cause the coralline to die back. It should come around though.
 
Top