Lighting for my Tri-color Acro

Genghis · #1 09/30/2001, 01:46 AM

I just setup a 30 gallon SPS tank w/ 150w MH and 10 gallon refugium. I had my water tested at my LFS and was told that everything was in the right ranges. I've noticed a pattern with when my acro decides to extend its polyps and when it closes up. I was just wondering if the coral prefers lower levels of light or if it's still acclimating to that amount? When I have my canopy in it's closed position, the coral will refuse to open up. When I leave my canopy open ( top is straight up, not in the 45* position) the polyps will open up. This isn't something that happens instantaneosly, but probably after 30 minutes. The polyps will remain to stay open as long as I leave the canopy open, but will close up slowly after I place the canopy down.

I also have another acro frag that refuses to polyp at all, day or night. I went back to the LFS and checked another frag that came from the same colony and noticed it didn't open its polyps in the store. I'm not totally sure, but it looks like its losing some color.

Sorry for the extraordinary long post, but I just wanted to make sure everything is going well. Any help will be appreciated!

MiNdErAsR · #2 09/30/2001, 09:17 AM

You just set up the tank? Yesterday? Last week? Last month? For the most part Acropora spp. need a mature tank (~1 year) in order to thrive. Tell us more about your system.

Is the 150w HQI (double ended)? If so, perhaps you don't have the UV shield in place. You canopy should have no bearing on whether the coral extends polyps or not. Does your canopy seal the tank (i.e. glass lids)? Perhaps you're limiting air exchange and driving O2 levels down.

We need hard numbers. Sometimes the LFS' idea of "the right ranges" isn't exactly up to par. What test kits are they using, and what did they test for? Not all brands of test kits make the cut, for the anal reef keeper in me.

And finally...if the colony from which the frag was taken was dieing, it *may* affect all the frags. Not always the case, but sometimes. Bleaching is certainly a sign of a problem, but not necessarily the end of the world. In the proper conditions the coral can make a come-back.

Genghis · #3 09/30/2001, 01:57 PM

The tank has been going for about 8 months. I'm using a Magnetek 150w MH ballast (not an HQI bulb) with a bulb that supposedly has a "50k" rating from it's manufacturer and no glass lid. From the pictures I've compared the colors to, it has a little more blue than the 10k, but less than the 12k sunburst. I plan on upragding to a 175w or 250w MH w/ a 10k german bulb. For the filtration, I use a refugium and a CPR bak-pak skimmer that I turn on every now and then. The test kits that my LFS seems to use the most are made by Hagen. Which test kits would you recommend using?

The acro that was bleeching has lost the purple tips, but still retains the light brown-pinkish color that covers the rest of it. As for the tri-color, it seems to be doing great.

therman · #4 10/01/2001, 08:24 AM

Many Acropora will only extend their polyps to any degree at night, capturing nocturnal plankton, gametes, etc.

When you raise your canopy up and the light level drops, your coral thinks its night, so out come the polyps.

The coral not extending its polyps at all may have a problem, but then again, some acros just have really really tiny polyps.

HTH

Tim