how to light a 120x24x30

[swflfisher]

Let me start out by saying I know nothing about lighting except for some threads I have been reading on here. This is going to be my first reef tank. Also tank is 1 in with euro bracing? It has 3 large opening in the top. So do I need to get lights for those openings or can the light go thru the tank? All opinions would be appreciated

[dlp211]

I am by no means an expert, but basically you have 3 lighting solutions right now. T5, LED, and MH. Now depending on what you want to keep will determine what kind of lighting and how much you need.

If you want to keep SPS all the way to the bottom, T5 is out, and you are going to need some tight optics on the LEDs. If you go MH I believe, but am not sure, but you will need to use 400w MH as 250 only really is good to 24".

Also, if you go MH, you will need 5 pendants to get good coverage, and I am pretty sure about that as each MH covers about a 24x24 area.

LEDs are more difficult as each manufacture specifies different coverage and depth. You can DIY, and there is a lot of info, but make sure you are reading the newest info out there. Royal Blue/Cool White was all the rage, but people are using a more Neutral White/RB/Blue combo, and even adding some greens and reds.

I will say this, the more info that you give, the better the help you will get ie, what you want to keep in your tank.

hth
dave

[swflfisher]

I want to start out "easy" in terms of coral to get the hang of it. From what Ive read I dont think I want to mess with LEDS as it seems complicated. My concern is will any decent light(good par numbers) make it thru 1" acrylic?

[dlp211]

Well you shouldn't be pushing light through acrylic. All your light should go from bulb/reflector, through the shield, air, then water. Adding another layer will diminish the light, more so with glass and less with acrylic, but nonetheless, it will be diminished.

In your case, I would def look at a MH/T5 setup. They make fixtures that are pre-built that support this, or you can once again DIY and save some money.

I think 5 MH pendants and 4 rows(2 on each side of the MH) of T5 would give you great coverage and flexibility.

T5's are now able to be dimmed, so you can do a ramp up and then bring your MH's on. ie: ramp T5's 0-100% 4 hours, T5/MH 4 hours, ramp T5's 100-0% 4 hours.

I will also point out once again, the strength of your MH's is going to be determined by how deep you want to place the corals. I think, but once again, I am not an expert, that you could do 250W MH and put some softies/LPS towards the bottom, and keep the SPS higher in the tank.

Things you should also consider is how deep your sand bed is going to be as this will effect how deep you need to penetrate.

[swflfisher]

thanks... one more:0 what are actinics?sp...and what is their intended use

[dlp211]

Originally Posted by swflfisher

thanks... one more:0 what are actinics?sp...and what is their intended use

So actinic lights are basically a blue/purple light. Basically, it is the light color that gives your tank that POP factor. It really fluoresces the tank.

I will say I forgot of another option which is MH/LED which I think would work real well for you as well. So instead of T5's, you would have your LED's.

Color temp. is a whole 'nother topic, and it gets pretty in depth pretty fast and the best thing for you to do is go look at the way tanks are lit, then try to emulate that lighting.

[swflfisher]

so confusing.... thank you

[dlp211]

What are you confused about? I know it can seem overwhelming, but once you get your head around it, it is pretty easy to understand. Of course, there is more then one way to measure color, and each is important in its' own way.

I will say, most people light their tanks at either 14k Kelvin or 20k Kelvin. This is a good way to measure the way the human eye perceives light, but it is a poor way of measuring the actual color of the light.

20k is going to look really blue, and will really make the colors pop, 14k is still going to be blue, but less so, and will give you some pop, but not as good as the 20k. So you may ask why doesn't everyone run 20k? Well, it makes it look very artificial and 14k is a good balance between reality and the pop that we are trying to get.

[Haplochromine]

Don't try to shine light through that acrylic. Your aquarium is designed for separate pendants to go over each opening in the top of the aquarium. Metal halide is a common use for this, and 250W halides will do fine for you in each opening.

LED is a relatively new technology but there is a lot of good info on them here.

T5HO lights would also be ok for you. A 6 or 8 bulb unit would grow more or less anything that you'd like, depending on depth in the aquarium for the light to penetrate.

Actinic bulbs are bulbs in the blue spectrum of light. They produce that blue glow that marine tanks are associated with. They are used as supplements for whiter/yellower lighting that comes from your main lighting. They aren't required, but they do produce a nice colour, depending all on your light setup.

[swflfisher]

were is a good places to look at light fixtures?

[dlp211]

Your LFS, or a local reefers house.