Coralline algae under VHO vs MH

[Andy]

Hello

I have 2 saltwater setups. One is a 20 gallon tall reef lit by a single 175 W, 10 000K German MH pendant and the second is a 280 gallon reef lit by 6 VHO fluorescent bulbs. The coralline algae in the 20 tall is very light purple to white in colour. Live rock that initially had dark reds and purples are now white. In the 280 gallon reef, coralline algae is medium to dark purple in colour. At my LFS, all tanks are lit by NO fluorescent bulbs and their coralline algae is vibrant medium to dark purple and deep red. I've always wondered whether I'm doing something different to get the lighter colours or whether coralline algae just doesn't grow in the darker colours under more intense lighting. What experiences do everyone out there have to offer. Anyone have deep purples and reds under MH and VHOs. If so, are you adding any additives that might be responsible for your success.

Thanks,

Andy

[Greg Moore]

Andy
In my some what limited experience with coralines, I have found that in general, the brighter the tank, the lighter the coraline that grows. This also applies to where it grows, ie darker maroon colours under overhangs, brighter pink/purples facing lights.

I have also seen a great many times where people will mention a drop in coraline growth when they switched to halides and/or a bleaching of it. Some of the darkest purples (usually found on live rock) seem to only survive best under NO lighting, bright pinks under VHO etc etc..

Greg Moore

[Dman]

My experience is the more light, the lighter the coralline. When I upgraded from NO to HM, my coralline went from a lovely shade of purple to white.