Lots of burned corals :(

[MikeG]

I am guessing it is from light as I run a single halide and it is mostly corals that are in the center of the tank under the bulb. Funny thing is I changed the bulb 3 weeks ago. The first week I did drop the photo period a bit as the fixture is already about as high as it can go without modifying how it is hung.

It is really bad on a lot of flat parts of corals that are more directly exposed to light and and on some tips as well. Both SPS and LPS. I switched from a Ushio to an XM both 10K 400W. Based on Sanjays tests the xm puts out a lot more light. Just surprised it took 3 weeks to cause problems (2 weeks at full lighting schedule).

I am hesitant to turn the halides on and cause stress in already hurting corals. Should I leave the MH off for several days and just run actinics and then real slowly ramp up metal halide time like increas 1 hour every few days and bring it up over a couple weeks?

Am I being too cautious? What would you do?

Within the past month I have also added a calcium reactor. Alk and calcium have been pretty consistent at 8.5 and 475ppm.

I started using UV 24x7 to help with water clarity. This could definately help light penetrate more casing issues however I have always run heavy carbon that would have the same result.

I also replace my ferric oxide 3 weeks ago but measured phosphate levels right after I changed it and they were 0.00-0.01 using a photometer so I don't think it would have anything to do with the amount of ferric oxide put in the reactor. (Same amount I have been using for about 4 months, 1/2 full phosban reactor)

 

[Liam]

i would just reduce the photo period Mike. maybe by about 3 hours a day

 

[MikeG]

So you would give them some time with out light to try to recover a bit. The parts that are burned are completely white, looks pretty bad.

 

[Liam]

So you would give them some time with out light to try to recover a bit. The parts that are burned are completely white, looks pretty bad.

i'm thinking going from too much to none may be a shock in itself.
IMO you would be better with a reduction.

 

[MikeG]

i'm thinking going from too much to none may be a shock in itself.
IMO you would be better with a reduction.

Same reasoning I have gotten elsewhere. I think I will cut it back to 2-3 hours and slowly add a few minutes a day.

 

[NateHanson]

I always wonder whether giving tons of light for a shorter time is much of a relief for an ailing coral. Maybe if you can't raise the light it would be good to put a couple sheets of screen material on a piece of eggcrate for a week to give them a break, and try to adjust to the new light.

Less intense light for the same period seems less stressful to me. I don't know, however, if corals feel the same way.

 

[Mike A]

Mike, any improvement since you reduced the lighting period ?

 

[JayM]

If you need eggcrate, I have a couple of sheets hanging around

 

[MikeG]

Mike, any improvement since you reduced the lighting period ?

Things havn't really gotten any worse, it is down to 3 hours right now. It is just a few corals probably about 10 that were in the middle of the tank. Several others lightened up but still look healthy with good polyp extension. I will bring it back up real slow and hopefully everything wil recover.

If you need eggcrate, I have a couple of sheets hanging around

I think I should be all set Jay but let me know if you want me to drop off that pump for you sometime this week Thanks.

 

[Liam]

it will probably be a very slow return to their former glory Mike. I have found corals that get too much light take way longer to get their color back than those that had too little.
I have a few myself right now that i over blasted

 

[RayD]

How about maybe changing the color of the bulb(s) from a 10k to a 20k then slowly increase the photo period? A bluer bulb may be less of a shock.

I just went from 2 x 250 SE to 2x 250 DE and what a difference! I cut the photo period and brought it up slowly over the past couple of weeks. Hoping to be back to a full 8 hours by the end of next week.

 

[MikeG]

How about maybe changing the color of the bulb(s) from a 10k to a 20k then slowly increase the photo period? A bluer bulb may be less of a shock.

I just went from 2 x 250 SE to 2x 250 DE and what a difference! I cut the photo period and brought it up slowly over the past couple of weeks. Hoping to be back to a full 8 hours by the end of next week.

That is what I am getting away from. I went from 14K 250W to a 10K 400W. I raised the reflector a few inches and had no issues but the 400W Ushio bulbs was maybe 12-18 months old. I then switched to 400W Xm 10K which was a new bulb and noticably brighter but only reduced the photoperiod for a week and then brought it back up. I would rather not switch bulbs agains since what is there now is what I am going to be running. Just need to take my time coming back up. At least MOST of what got burned were not rare corals.

 

[paulthomas]

Bummer. Sorry I couldn't be of help Mike. I can offer moral support if need be?