actinic lighting

[StirCrazy]

I was at albrite lighting today and they can get in NO actinic/03 bulbs for 17.00 each.. all the lfs around here want about 30.00 to 50.00 for the same thing. with a workhorse 7 (aprox 50.00) I can run 4 bulbs. will 120 watt of NO actinic be enuf to compensate for 192 watt of PC?

Steve

[reefburnaby]

Hello,

192W of PC .... what colour ? 6500K.

- Victor.

[Silverfish]

Hey Steve, that should look pretty cool! Allbrite is a cool shop to get stuff, my friend Mark works there. I am going to see what price he can give me on Icecap 440 & 660 ballasts. If he can beat J&L then why not? I get pretty much all my lighting from him. Put two 24w 6500k pc's over Meighans (my gf) 15g with two no actincs, and I like it almost as much as my MH & actinics on my 60g! images/smiles/icon_biggrin.gif I also put two of those pc's over my sump/refugium, grows caluerpa and halimeda quite nicely.

[Reefmaster]

i paid $4.95 for a 40W phillips 03 actinic bulb from albrite!! what the heck is $17 about???

[StirCrazy]

hmm maby the 36" is more expensive.. or maby I just need you to go buy it for me images/smiles/icon_biggrin.gif

Silverfish, if ya get a price let me know I might be interested in a ice cap to light up my actinics.

Victor, one is 6500K and the other is 10000K

Steve

[ 16 November 2001: Message edited by: StirCrazy ]

[ 16 November 2001: Message edited by: StirCrazy ]

[StirCrazy]

while we are on lights .. something has bothered me about the way people figure out there light.. everyone says to get to so many watt/gal but I feel watt/square foot would be a better estamation .. am I out to lunch or what?
the way I see it with 312 watt of light (after I get my actinics) I will have 6.24watt/gal in a 50 gal tank.. but measured the other way I would have 69.3 watt/ square foot, I am interested to hear what other people have /square foot.

Steve

[DJ88]

IMO neither are really accurate.

With W/gal it is misleading.. As is W/ft^2. With both all you get is a ratio. With no real reference. It makes it seems that 400W of NO is the same as 400W of MH. Which it isn't. Not even close.

With W/ft^2 you are assuming you have the same intensity over all of the surface area of your water. and you don't. Especially if you have a MH. the intensity is focused over one spot mainly. With tubes it is spread out even further. With this spreading of the light over more area the intensity decreases massively.

As with any measure of light in a tank the main concern is how DEEP your tank is and how that light penetrates it. With each type of lighting your intensity increases and therefore the depth at which the light penetrates goes further. This is going from NO to VHO to PC and then MH. The light coming out of a tube(NO & VHO) is pread out over a long length. So you can only say that for each inch of a 48" NO tube it has approx 0.8333 w per inch of tube and that is radially. A MH puts out 400W of light in an element that is approx 2 inches long. As a guestimate that is 200W per inch of source. Can you see where I am getting at?

For example I had 320W(at one point 400W) of NO light on my old 90 gallon tank. The few corals I tried existed, nothing more. Most receeeded. But I had no growth and had to have them inches below the surface even for that.. in my 33 I have MH and VHO. And get explosive growth on most every SPS I put in. That is the only way to describe it. They are the same depth or in most cases deeper.

The intensity of the light in your tank decreases exponentially as you penetrate. So IMO both ways of measuring are kind of deceptive. The only way to really compare lighting is to measure the actual intensity of the light in various spots of your tank and then make a visual representation of this data. An easy way to do this manually would be to sit down and figure out small areas of your tanks water surface and sit and look at what light sources are above that spot. Even there you have a problem with this as light sources emit light radially. Not all in one small beam. You can assume that all of the .83W/" of NO is going down. But we know it isn't. This is where reflectors are useful. But even then there is light lost. If it all went into your water the inside of your lid wouldn't be lit up.. images/smiles/icon_wink.gif I know, semantics but you get my point right? The only way to know how much light your tank is recieving is to measure it at the waters surface and all over the surface. Then show this in a graph to aid with passing this information across.

IMO adding how much wattage you have and using an arbitrary figure to create a ratio isn't a useful way to express how much light you have. There are too many variables.

I say just use your eyes and decide if you have enough light for what you are hoping to do by gaging it against a similar tank that is successful with what you hope to keep. Follow others leads. ie MH for SPS, Clams, LPS and softies, PC for softies n some LPS, NO for fish only. Even then it is dependant on how deep the light has to penetrate.

Did you get all that?? images/smiles/icon_wink.gif images/smiles/icon_biggrin.gif

[ 17 November 2001: Message edited by: DJ88 ]

[StirCrazy]

hehe ya I get it images/smiles/icon_smile.gif thanks, I kinda new that from fresh water planted tanks but I guess I was trying to figure out a way to guage simular conditions.. ie.. if dept is the same and type of lighting is the same. oh well .. now.. is there some sort of light intensity meter that can be submerged in a salt water tank for doing spot readings? oh ya .. and that is afordable images/smiles/icon_biggrin.gif

Steve

[reefburnaby]

Hello,

For the most part, I agree with Darren (except follow the others lead part). If you have a camera that can do spot metering (most SLRs), then you can use that to do some light measurements.

As a sample, my 20 reads 1/60 @ F2.8 with ISO100. The reading is made on a grayish surface something like live rock. It is also made on the rock that is near the center of the tank, but at the bottom of the tank.

I will bring my camera over to meeting, take a spot meter and see how it compares.

Darren, maybe you can use your camera do a light reading of your tank and compare.

- Victor.

[DJ88]

Hey Victor,

I'll do that.. I'll let ya know.

I will say I didn't mean for anyone to just follow. But to look into what has brought success to a tank in keeping(an excellent track record) what the person researching wants to keep him/herself.

[ 17 November 2001: Message edited by: DJ88 ]