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Amethyst · 08/16/2014, 01:36 PM

I have a small reef setup (20g long tank) that currently has 2 mushroom corals, a couple of pieces of Hollywood stunner chalice coral, a piece of montipora, a candy cane coral, and one that I forgot the name for but is branched, with pinkish polyps and bright orange mouths. All are quite small still, as I've been adding them over the last few months. I also have several varieties of macroalgae, live rock and live sand, and a bunch of several types of snails as clean-up crew. Eventually I may add a small fish or two.

I have been temporarily lighting the tank with the hoods from two 10g tanks with power compacts - mix of 50/50 bulbs and 6500-6700 bulbs. I am in the process of building a hood with a more permanent lighting setup, but before I start building I have questions.

My original plan was to use a total of 8 cfl bulbs, 10 - 15 watts each. To that end, I bought 2 three-bulb sockets and 1 two-bulb socket at my local hardware store, with the plan to put blue bulbs in two, 50/50 bulbs in 2 and 6500-6700 bulbs in 2, wired so that I could turn on the two blue first, then the 50/50, then the others and then reverse for turn off, so that it would simulate the natural daylight cycle in intensity and spectrum through the day. However, I can't find any all actinic blue bulbs that screw into regular sockets. Hence my first question:

Blue vs actinic blue - is there a difference? Is it just a matter of the blue color that penetrates farther into the water than the other parts of the spectrum, or is there something special about "actinic" lights other than the color? For instance, are the blue leds they sell for "glofish" tanks the same as the blue LEDs labeled "actinic" that are sold for reef tanks?

Second, the guy at the hardware store was concerned about the heat output of 8 bulbs. If I use LEDs for the blue and only 6 other bulbs I assume that will help cut down on heat. I also have heard that aluminum somehow disperses heat, as well as reflecting the light. If I use some thin aluminum reflectors, will that help? Will moving the lights farther from the water to help with heat defeat the purpose of having the wattage and spectrum I'm creating? Will I still need some type of fan or chiller? (By the way, I live in the northwest, and it usually doesn't go above 80F, so I don't have to worry much about ambient temps raising water temps, although we do have the occasional heat waves where temps go into the mid 80s or higher. Last week it was in the upper 80s to low 90s for a few days, and all of my tank thermometers were showing water temps in the low 80s, but that is unusual.)

Finally, what is PAR, and how does one measure it? I noticed someone using a light meter to measure PAR in another post. Is there any other way to estimate PAR?

I'm also considering moving the whole setup to my 29g tank, which would mean the light will have more water to penetrate, although the width/depth measurements would be the same.

Any and all feedback/advice/information graciously accepted. Thanks in advance.

08/16/2014, 01:36 PM	#1
Amethyst Registered Member Join Date: Apr 2014 Location: Near Seattle Posts: 63	Lighting questions I have a small reef setup (20g long tank) that currently has 2 mushroom corals, a couple of pieces of Hollywood stunner chalice coral, a piece of montipora, a candy cane coral, and one that I forgot the name for but is branched, with pinkish polyps and bright orange mouths. All are quite small still, as I've been adding them over the last few months. I also have several varieties of macroalgae, live rock and live sand, and a bunch of several types of snails as clean-up crew. Eventually I may add a small fish or two. I have been temporarily lighting the tank with the hoods from two 10g tanks with power compacts - mix of 50/50 bulbs and 6500-6700 bulbs. I am in the process of building a hood with a more permanent lighting setup, but before I start building I have questions. My original plan was to use a total of 8 cfl bulbs, 10 - 15 watts each. To that end, I bought 2 three-bulb sockets and 1 two-bulb socket at my local hardware store, with the plan to put blue bulbs in two, 50/50 bulbs in 2 and 6500-6700 bulbs in 2, wired so that I could turn on the two blue first, then the 50/50, then the others and then reverse for turn off, so that it would simulate the natural daylight cycle in intensity and spectrum through the day. However, I can't find any all actinic blue bulbs that screw into regular sockets. Hence my first question: Blue vs actinic blue - is there a difference? Is it just a matter of the blue color that penetrates farther into the water than the other parts of the spectrum, or is there something special about "actinic" lights other than the color? For instance, are the blue leds they sell for "glofish" tanks the same as the blue LEDs labeled "actinic" that are sold for reef tanks? Second, the guy at the hardware store was concerned about the heat output of 8 bulbs. If I use LEDs for the blue and only 6 other bulbs I assume that will help cut down on heat. I also have heard that aluminum somehow disperses heat, as well as reflecting the light. If I use some thin aluminum reflectors, will that help? Will moving the lights farther from the water to help with heat defeat the purpose of having the wattage and spectrum I'm creating? Will I still need some type of fan or chiller? (By the way, I live in the northwest, and it usually doesn't go above 80F, so I don't have to worry much about ambient temps raising water temps, although we do have the occasional heat waves where temps go into the mid 80s or higher. Last week it was in the upper 80s to low 90s for a few days, and all of my tank thermometers were showing water temps in the low 80s, but that is unusual.) Finally, what is PAR, and how does one measure it? I noticed someone using a light meter to measure PAR in another post. Is there any other way to estimate PAR? I'm also considering moving the whole setup to my 29g tank, which would mean the light will have more water to penetrate, although the width/depth measurements would be the same. Any and all feedback/advice/information graciously accepted. Thanks in advance.