Seeing Purple

[cubano]

When I first started my tank, I had a variety of colors in my coraline algae. The live rocks showed pinks, yellows and purples. I've had my tank set up for about four years, but all I now have is blanket of purple coraline covering all the rocks and some of the glass in the back. Is this the same algae that turns purple as it ages, is it my lights? It does make my tank look darker and a lot less colorful.

 

[bang guy]

Stronger light sometimes results in the brighter colored coraline becomming dominant. The purple coralline likes darker areas.

 

[diadema]

water perameters play a part too. I found with my old setup running Instant Ocean, 1 color became predominant in the MH area and another in the shaded area.
With the SAME rock, in a new tank and another salt brand (this one higher in Calcium and Magnesium) and a pretty frequent strontium routine, I have lots of colors.
Bright red with orange streaks in a plating coralline is my favorite.