Help: New MH Bulb- Avoiding light shock

[Alpental]

Hey everybody,
I'm new to reef keeping. I've kept all kinds of fresh water tanks but I became bored with them. So here I am.

Here is the question. The tank I have is an established 55 Gallon corner tank (4 years old) and the coral inhabitants include- Big Ol Colt Coral about 2 years old. The corals I've added since I acquired the tank a couple of months ago- Frogspawn, green striped mushrooms, some zoos, green star polyps, and very recently pink poccilopora and florida ricordea. Everything, seemed very happy under a 175 watt 10,000K MH with a 28 watt actinic PC. The PC is new but the MH could be anywhere from 6 months to a over a year old. So I ditched the MH today and replaced with a 175 watt 14,000K MH. Any advice on acclimating the corals to this new bulb?

Thanks

I won't normally place smiley faces on my posts but since this is my first thread I feel it appropriate.:shock:

 

[diablo]

well I would shorten the photo period and then gradually raise the time back to normal.

 

[steve-s]

You shouldn't have any issues. If I'm not mistaken, increases in the light spectrum (10k to 14K) are generally not a concern. It's when you drop the rating, especially when going from a very "visually" blue (20k) to a white/yellow (6.5-10k) spectrum. Then it would be wise to actually shade the tank with layers of screen material and slowly allow the inhabitants time to adjust over several weeks running the same photoperiod.

The sign to watch for is the corals lightening in color. The main ones will be the shromms and "LPS" type species. If their colors remian healthy, you should be all good.

Cheers
Steve

 

[Sk8r]

If all else fails, use some windowscreen in black to reduce the light reaching the tank.

 

[NeuroDoc]

Steve,

I thought that the issue was that old bulbs will loose luminosity (intensity) over time, that is not perceptable to the human eye (primarily because it occurs so slowly). So that when a new bulb is put in, no matter what the color rating, the light is much more intense to those organisms that use light for survival. I have noticed that in replacing bulbs on my tank that it always seems brighter with the new bulb, when I hadn't noticed the old bulb becoming dimmer.

(dimmer - is that even a word when used in the context above? I don't know, but I think you get my drift.)

 

[Alpental]

Looks good

It's been a couple of days and so far so good. Everything looks happy. I did shorten the photo period from about 10 hours to 4 hours. I will increase by an hour everyday.

Thanks for the input so far.

 

[steve-s]

I have noticed that in replacing bulbs on my tank that it always seems brighter with the new bulb, when I hadn't noticed the old bulb becoming dimmer.

The bulb isn't dimmer, it's just a spectrum shift. The result being the same as I noted above. Going from a lower kelvin (old bulb) to a higher kelvin (new bulb) should not be an issue.

Cheers
Steve