New halide bulb - coral retraction?

I would cut back on hours and raise it as high as you can. Run for only a couple hours a day, try to spot feed your corals if they will allow while they heal, and then gradually increase the number of hours. I think we all underestimate how powerful these bulbs are. My friend grows SPS on the bottom of his 25" deep tank with the bulbs 18" or so above the water surface with 250's. The Ushio is a much better bulb than the Coralife. Sorry to hear of your troubles - the corals will recover. They're pretty resilient, especially the softies you have.

 

Thanks Zach. Perhaps I will try raising it more and moving the affected corals into some shade near rocks.

This kills me. The day before I was ready to show off my tank. Ugh.


Anyone else?


Love a few opinions before I do this.

 

Sounds like UV burn. Is the UV shield on?

I'd say the Coralife versus the Ushio will be a huge PAR difference. What Ballast are you running?

 

You know it is interesting you brought up UV. The UV shield is on, but this is an original Aqualight where the semi-circle UV shield does NOT cover the bulb all the way. They fixed that in the 2nd generation of the lamp. So what I have done is rotate the shield so that a majority of the bulb is covered. However, one edge of the bulb is still exposed. I have the fixture tipped a little bit to help negate it, but it has bugged me. EDIT - the ballast is the original Aqualight ballast - not sure what that is off the top of my head.

My Cardinal fish hide in the shade all day until night and I've wondered if it had to do with the UV although I've been told they are pretty nocturnal.

My plan which I thought of yesterday is to replace the metal slip-on deflector shields (normally where glass would be) with UV filtered glass ASAP. (What kind of glass do I need by the way?) I will do this tomorrow.

Glad you mentioned UV as this has been nagging me and may explain what I am seeing now.

 

Hey Matt...FWIW, I just changed over from 8x54w T-5 to 3x400w Ushio MH 14k. That is basically triple the lighting as far as wattage goes. I shortened my photo-period to 4hrs to start, and have added 1/2 hr every 2 days. (thanks to Otty's suggestion) I still run the actinics 11hrs. I have alot of the same corals you mentioned, and they are literally thriving. Even the first day. I think you may persue the U.V. avenue. I just dont see where the light should make that much difference, based on what I am experiencing here.

 

Thanks Robman. I am really suspicious of the UV now. I am messing with the light right now. I measured for new UV filtered glass and I am trying to get the current shield over the bulb more. About a 1/4" of the bulb is exposed along the side. I put the original mount back together and it looks like I can raise the bulb to about 20". I'd love to get that new UV glass today but I seriously doubt anything is open on Easter.

 

Good thought on UV. That's pretty important, for your eyes as well.

 

AYe. Know off hand what type of glass I need that filters UV?

 

Matt, sorry to hear you're having such difficulties. I dont know much about getting new bulbs for MH as I dont own MH yet, but I can say from owning lizard tanks and having to provide them UV light it refracts everywhere. A living plant on my table next to my lizard cage died within the first week of a new UVB bulb for my beardie. I then realized that the extra light emiting from the top of the light fixture that wasnt 100% enclosed was killing my nearby plant life. Closed it up, got a new plant, hasnt been a problem since. So my point here is although you are orienting the protective shield better it probably wont wind up doing much. The UV is going to refract like crazy in the water and hit lots of things not just what you think you can visually see that unexposed light portion hitting.

 

I believe it has to be tempered glass.