Anemone!

[Zarathustra2]

Actinics are for you, not your corals. The blue light they add makes colors pop a lot more. Also, many corals/sea creatures flouresce under the heavy blue light. The blue is useful for your critters to a certian extent but just don't put out the wavelengths needed for photo-synthesis.

As a rule of thumb I take out actinics from my light calculations. Some people count them as 1/2 of thier wattage. So in your case for a 55G you are looking for ~200-250w of "daylight" type bulbs (10k Kelvin rating.) You would probably want to add one or two actinics so the colors of everything looks good to the human eye. A lot of people go with the 50/50 route. So, 3 10k bulbs and 3 actinics.

As an aside I've been using 14k Metal Halides on my tanks recently with no actinics and it looks great. I think it gives a great color to everything.

[Christian]

kool but I only have room for 4 bulbs on my 55g tank because it is a show tank, its with is only 1 foot.

[Zarathustra2]

I think you would be well served by going to 2x150w Metal halides. Just in the space savings it would be worth it. If your fully bent on the T5 fixture then I think i would do 4 14k bulbs. I've never really played with T5s though so I don't know how it would end up looking.

[Christian]

well right now I have one 18,000K with a actinic. I'll put some pic's of the 18,000K with a 6,700K light but it's too yellow for my likes and it makes the algae stand out too much too.

[Christian]

after aqua scaping

[chrisfowler99]

I really like my T5 setup...and I paid out the nose for it...but I'm becoming more and more a fan of MH...I really don't want to switch, though.

[Christian]

well if it's enough light for what you want why switch?

[NonSequitur]

Have you tried to run just the 6500k + actinic? I'm not sure if it's the same with t5s, but with halides lower K rated lamps often have more PAR(usable light), so if you're not looking to change out your fixture you'd probably get the most usable light from 6500+18000 (whch you felt was too yellow), followed by 6500+actinic, then 18000+actinic.

[chrisfowler99]

well if it's enough light for what you want why switch?

It's plenty of light, that's not the issue.

I like the shimmer...plus some colors pop a bit more under MH.

[Christian]

I was going to do that in like november when i can get another t5 fixture for the tank.

[GKarshens]

Actinics are for you, not your corals. The blue light they add makes colors pop a lot more. Also, many corals/sea creatures flouresce under the heavy blue light. The blue is useful for your critters to a certian extent but just don't put out the wavelengths needed for photo-synthesis. .

From my reading and experience this is not entirely true. Although the daylight is by far more important, corals and anemones do need a blue spectrum light to properly produce the right zooxanthellae. At depth in the ocean the blue light penetrates further than any other spectrum. So the corals are used to this type of light and that is what they are designed to use. They will stay alive without it, but will most likely be brown or pale.

The watts per gallon rule is a good start but can be a bit misleading. 500 watts of PCs is not the same as 500 watts of Metal Halides. Metal Halides have much better penetrating force so will produce more light at depth. On a 55 I would look into a 6 bulb T5 fixture. With 4 day colored bulbs and 2 actinics. That should give you enough light to keep anything you want.

[Christian]

thanks