duration vs. bulbs

[LeslieS]

One of my light fixtures isn't working properly. Out of eight total 39w bulbs, only six are turning on.

I would rather wait to get new fixtures when I upgrade my tank. In the meantime, can I use only 6 bulbs but extend the photo period? Should I use all my available slots for white bulbs or should I still include actinics?

Tank is 30" tall 120 gallons
Everything photosynthetic is layered with the things needing the mos light about 6" from the fixture. I do have one 6" crocea clam about 18" from the fixture.
The only things on the bottom of the tank are polyps, mushrooms, and trachyphilia which are partially shaded loving it.

 

[meschaefer]

What size and most importantly how tall is your tank and what do you got in there?

 

[LeslieS]

Matt, I added more details to my first post. Thanks!

 

[ming]

can you try swapping out the two bulbs with two that work? it might just be a burnt bulb. i can give you an old 39W bulb if that's the case. if 1 bulb goes out, both bulbs on the ballast goes out

 

[LeslieS]

Ming, I just bought all brand new bulbs! I checked them in different sockets and the bulbs are OK.

One ballast has been blinking occaisionally. It always stopped if I turned the light off and then turned it back on. Now it either blinks constantly or just turns off. I will try to get it to work again tonight, but just want to know my options in the mean time.

 

[ming]

I think if anything, your corals will just slowly turn duller from less light. I would prefer to use all the slots for white bulbs because actinics only help it fluoresce. They definitely won't die from 6 bulbs anytime soon, and it'll probably take at least a couple of weeks before you notice much if any difference in the corals. I had my SPS tank running on 2 actinic only bulbs (6 total bulbs) for almost week when my ballast broke. No casualties, but my sps dulled out. I would think your 6 bulbs should be fine.

 

[meschaefer]

I think you will be fine as well. Use only your "white" bulbs as they will presumably have a higher PAR than the actinics. This should hold you over for some time.

As an aside:

When I did my upgrade I specifically set out looking for a tank that was no more than 24" tall, to avoid the necessity of moving to even larger bulbs. I run 250w MHs on my 24" tank, but felt I would have had to go to 400w MHs for a 30inch tall tank.

 

[LeslieS]

Thanks guys. I am working on getting a new fixture.