Pink Birds Nest with some sort of algae growing on the tips 9/23/11
Hey Crew,
<John>
I have a pink birds nest coral that has been in my tank for 3 months and showing stunning color and extremely fast growth during that time. Three days ago I upgraded the powerhead that was operating in its vicinity to a magnum 6, almost tripling flow in that area. The powerhead is controlled by a wave maker, but the flow was pretty much directed at the birds nest.
<Mmm... I would re-direct this... this genus, these species of stony corals don't live in situations of such high water movement>
Yesterday, I noticed that the beautiful whitish/pinkish growth tips are turning brown and there seems to be some brownish flesh blowing in the current (only noticeable on close inspection). From the looks of it, it was diatoms or some similar algae. At first I thought it was dead polyps, but this doesn't appear to be the case. It only inflicted the tips, and mostly on the side of the coral that's facing the powerhead. I always thought more flow was better for sps corals,
<Mmm, no; not so w/ all families, species, colonies>
but could the increased intensity of flow somehow leave the coral vulnerable to algae?
<Yes indeed>
This seems counter-intuitive....
Levels are NO4 <3>=0 , PO4=0,
<... need some/detectable nitrate and soluble phosphate>
ALK=9 dKH, Calcium=440, magnesium=1400
No other corals are touching or even near the birdsnest (only a Stylophora frag and an Acro frag (ample spacing provided). No other area of the tank appears to be inflicted with similar-looking algae. It's kind of like a brown dusting on the tips, and it comes off with a soft bristle tooth brush, which I've used for two days now. I first noticed the algae the morning after adding the new powerhead. Seems like quite a coincidence considering it was stable up to that point.
Thanks in advance for your help, and sorry that I cannot provide a picture.
I will try to upload one later this afternoon if it's necessary.
Underneath the "algae" the coral appears to still be healthy. Good color, polyps look like they're extended, but it's hard to see the smaller ones near the tips.
John
<I wish you were out here w/ me in Fiji... Easy to show ecoclinal variation by water movement, light availability, siltation extent and more... Bob Fenner>

New coral help... Pocillopora lgtg., Acanthastrea current...  1/14/11
Hey crew,
<Michael>
I tried to find some info about this question but never found a direct answer to this question, hope you can help. I just got a Pocillopora damicornis sps frag about 2 days ago. In the retailers tank it was under metal halide lighting high up. My tanks lighting is 2x55w 10000k/antic compact t-5s and 2 Ecoxotic stunner strips, 1 is 8000k/antic and the other is 8000k. I placed the coral about 6 inches from the top in a indirect current since this coral seems to favor less. I noticed that for the past 2 days the coral is losing its brown color but the polyps are keeping its green and are extended. Its turning a pale tan and heading to a white color. My question is should I move it down the tank?
<... do you have access to a PAR meter?>
or just leave it alone?
<I'd leave where it is>
I really don't want to lose it and it comes paired with a crab that lives on it so it would make him homeless. I also have a Acan which I was wondering does it favor less current or more?
<Less than Pocillopora spp.>
I have read so many different views on the Acan I just cant figure out which is best. I currently have it in a indirect low current.
<Likely fine...>
Thanks again for all the help.
Mike