Quick stats on tank.  90 Gallon that i have had running since the end of January.  Started out with 2 175 watt 10,000k MH bulbs and a 40w NO actinic.    The 40w actinic seemed be be getting overpowered by the MH's so I decided to add in 2 VHO superactinics.

Since this time my zoanthid has croaked (or seems like it.)  I had a small rock with them on it, they started to shrink very soon after adding the VHO's.  I tried several locations, to no avail.  It is totally shrunken up now, can't tell if its totally dead, but they never open.

My green star polyps on one rock seem to only open fully with NO lights now.  During the day there will be a few with polyps extended, but nothing like when I check the tank before work at 6:00am, its a veritable forest of swaying polyps with NO lighting.

So, is my 2 175w 10,000k MH, 2 110watt VHO actinics and a 40w NO Actinic tooo much for a 90 gallon tank?

Nothing else has changed besides the lighting.  (well, except adding the 10 gallon refugium, but i wouldn't think that could make a difference.)

Thanks, Troy.

No, there is no such thing as too much lighting (realistically speaking).  What you can have is too fast of a change in light which things can't adapt to quick enough. 

Or, too much light in that area for that specific animal.  So move the coral somewhere else.  Or maybe it is a different wavelenght from what they are use to.  But the tank can really never have too much light.

Adam

twflint- there is no way that you have too much light.  I have a 75 gallon tank with 2x250 MH and 2x110watt VHO actinics and I've never seen a "too much light problem".  My zoanthids are spreading like weeds right up to the surface of the water.  Here are two pictures.  The first is of zoanthids at the top of my tank, the second is of zoanthids at the bottom of my tank (two different types btw).

When I converted from NO to PC lighting my corals hated it.  Even though they should of done better in the brighter light, they stayed closed and shriveled. 

I eventually turned my main light on for only an hour a day, just let the blue actnics on the rest of the time.  I left it like this for a five days.  After five days, I then increased the amount of time the main light is on by 30 minutes and did so every two days.  After a few weeks, I had the 9 hour cycle I wanted and the corals were used to it and extended fully with the main light on.

Thanks again for the help guys.  I did cut down the time I had the NEW actinics on.  It does seem to have worked, may attempt Vaders way too.

Thanks again!

Troy

Hey I have a 55 Gal with 2x250 13k's and 2 VHO super act. 

Everything is fine and my tank is super bright .......too much light NAH!!!

Hope everything goes well for you!

Well, I am fairly new to the hobby and have learned a ton since I started but still remained confused about some things, such as lighting. 

So please help alleviate some of my anxiety.

My coraline algea has not looked so good for the past 5-6 months and continues to struggle.  For a long time my alkalinity was too low, now I believe that has been solved(calcium and alkalinity are checked regularly with salifert test kits).  With the corrections in water chemistry still no big improvement in the color of the coraline algea.  So then i began thinking that I had too much light(46 gallon with 2x55watt PC and 1 175watt MH 10K).  After reading the previous postings I guess I could easily conclude that I don't.  So any ideas why the coraline algea in mainly the light exposed areas tends to be dull in color if not dying, and why the coraline algea in the skimmer and filter is brighter than that growing on the glass which grows very well. 

Other questions:

How far from the surface of the water do most of you have your MHs?

Has anyone out there tried the 12k or 14k mh? if so is the increased blue light output noticable?

Thanks

My MH is about 5-6 inches from the water.  I'm currently using a 12k K lamp (sunburst).  I don't like it, too blue and not enought intensity.  I bought from http://www.marinedepot.com">www.marinedepot.com and chose that bulb mainly from the color comparision pictures they have there.  Well, my sunburst is much bluer then the picture, I wish I'd bought either the Usio 10k K or the Iwasaki 6500 K.

what is the benefit of using a 6500k bulb vs the 10000k lights? 

Thanks

Jeremy

about $40 cheaper per bulb and twice the life .

Most people who've used both say the 6500K bulbs result in great coral growth and most people who've used the 10k K bulbs like the coral's colors better.  The 6500K crowd contends that with vho atinic supplementation, the color is fine.  I think my next bulb will be the Iwasaki.

Lumens, I think, are important to coral growth, but when it comes to MH I think most people (myself included) choose a bulb based on either personal experience or the recommendations of others.  How many hobbists have the opportunity of try all or even most of the available bulbs and ballasts?  The simple fact that there is no consensus even as to what kelven rating is best, let alone which bulb, leads me to believe that you can't really make a bad desision?  I could be wrong though :)

JW - Danny recently put in 2x250 watt MH setup with 13K AB bulbs with 2x110 watt super actinic VHOs and we were worried that the bulbs would look too blue and not bright enough, but I would have to say it is a very pleasing combination. 

There are some great articles on MH bulbs and ballasts here for those that have not read them:  http://www.advancedaquarist.com/">http://www.advancedaquarist.com/

I don't have MH yet but I will when I get a big tank, so I read everything I can find.  I wish that LFS's would have 5 or 6 tanks with different bulbs right next to each other...  It would make the asthetic choice much easier.  I don't think the "what bulb is best for the tanks inhabitants" debate will every be easy to answer though.

Dave