Acropora turning brown

Casey · 03-16-2003, 08:14 PM

Need you help guys why is my purple acro turning brown he was purple when I bought him? Is it my 12k bulbs should I switch to 65k
like the tank he came out of? Casey

cyberchef · 03-16-2003, 09:16 PM

What watt was he under and what watt do you have in your tank. sounds like it's getting more light than it's used to. The brown pigment is usually a sign that it's protecting itself from getting a "sunburn"...

Casey · 03-16-2003, 09:18 PM

he was runnin 440 watts of vho actinic and 2 250 watt 65 ks.

cyberchef · 03-16-2003, 09:47 PM

Quote:

Originally posted by Casey
he was runnin 440 watts of vho actinic and 2 250 watt 65 ks.

What are you running?

Casey · 03-16-2003, 09:49 PM

190 watts of vho actinic and 675 watts of 12k Sunburst Mh

mikeMersot · 03-17-2003, 12:14 AM

I've posted this before but,

The Elusive Blue-Tip Acropora

David Grigor · 03-17-2003, 03:14 PM

In my experience, usually means not enough intensity but not always. 12K Sunburst while may look aethetically pleasing doesn't score very well in this category.

Casey · 03-17-2003, 03:29 PM

Quote:

Originally posted by David Grigor
In my experience, usually means not enough intensity but not always. 12K Sunburst while may look aethetically pleasing doesn't score very well in this category.

I wouldnt think that is the case since other acros are fine and clams to,but anyway I have decided to change over to 65k bulbs which should be a bit brighter since sunburst are not and Im installing 200 more watts of actinic. Casey

David Grigor · 03-18-2003, 09:08 AM

I have had many 150W, 175W, 250W, and 400W MH. Purple in general ( as there are no absolutes and varies from coral to coral ) is a pretty typical to loose because of intensity. When upgraded to 400W 10K Ushios years ago, many corals turned purple that I had for years under lower wattage MH. Currently, purple is very typical color that when it starts to turn is a sign need to change the bulbs. So intensity has to be a factor. I believe it is more than just overall intensity but concentrated more in the higher end.

wasabi · 03-18-2003, 09:29 AM

I WENT FROM A VERY BLUE 400 WATT BULB TO A 10K USHIO AND IVE BEEN VERY HAPPY. THE 65 KS ARE TWO YELLOW/GREEN FOR MY LIKING. I STILL SUPPLEMENT THE USHIO'S

Casey · 03-18-2003, 01:57 PM

Hummm the bulbs are brand new one week old so cant be that might be intensity I dont like 10k ushios although they are bright I agree,Im going with 65k because I have been told it is closest to natural sunlight although I will have heavy actinic supplement.

David Grigor · 03-18-2003, 02:18 PM

Its not the age of the bulb. It's the choice of bulbs. 12K put as frankly as possible are very lacking in intensity even the 400w version.

That was just an example that when the 400W 10K started to age you would notice the color change. Which I conclude is due to drop off in intensity. Which probably is still higher intensity than 250W or 175MHs 12ks are even capable of brand new.

Since you stated the coral came from 65K, pretty certain it will help. But that doesn't mean every coral will turn nice color under the 65K. While I do agree the 250W 65K is a choice for 250W MH by the time you throw enough actinics at it, IMO you might as well bumped up to higher K 400W MH ( if coloration is more important than growth ).

Casey · 03-18-2003, 02:24 PM

David I understand now well I guess I will use the 250 since that is what I have and replace the 175 watter with a 250 watter I know some of the corals wont look as good I just want to see if i can get the acro back to purple. Casey

grazhopr · 03-18-2003, 02:29 PM

Very interesting article, mike.

Graham · 03-19-2003, 01:45 PM

cyberchef, et al...

Brown is generally a good indicator that the coral is not getting enough light - or rather less light, not that it is getting too much. Too much light will generally give you a shift to a nice white color

. The zooxanthellae are brownish-gold and when the coral is not getting enough light, it will produce more zoox to increase metabolic products back up to where it needs them. I've seen a bunch of under-lit tanks over the years and just about every "higher light requiring" coral (acros, montis, etc..) was brown. Photoadaptive pigments are rarely brown, as it is a redundancy since the zoox are pigmented in that range to begin with (they are already reflecting that portion of the spectrum).

In my experience, a coral will bleach from too much light a lot faster than it bleaches from too little light, thought that definitely does happen.

As for bulb changes, I use a drop in coral color intensity as a good guide that not as much pigment is being produced to shield the zoox. from the intensity of the bulb - usually around one year depending on the bulb. I've used sets of Iwasakis for over a year with no ill effects.

Coincidentally, I recently switched to 250W Ushios and quite a few of my hard corals have started the shift toward purple. I think I may go back to 'sakis....if I remember correctly, 10K bulbs are very monochromatic - a large portion of the spectrum is in that purple range, hence the purple colors. Also why you generally see the more intense blues beneath high K bulbs like Radiums.

That's my take...