2 + 2 = 4 ????

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oldfishead

Aquarium Advice Regular
Joined
Oct 6, 2006
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upstate n.y.
hope ya don't think this is a real STUPID question , i just dont know .
lighting - 1 x25w. + 1 x 25w. = 50w. or does 25 w. = 25w. nomater how many there is ??? "I'M EMBARRASED"

thanks - oldfishead !!!
 
No, you have it right 25w+25w = 50w. I believe what matters is:

1) What you have in your tank (i.e. corals (sps, lps etc...) anenomes, clams, etc...)
2) How deep your tank is. It takes more watts/gallon to reach the deeper parts of the tanks

I am sure someone with more experience than me shall correct if I am wrong
 
To answer this, think about the intensity of light of a 25w bulb. Now put two of them, side by side. Now put one 50w bulb next to the others. Which would be brighter?

It does not make sense to me either, yet it kinda does. We are not supposed to add the wattage together, yet we are forced to when people ask us how many watts per gallon we are running...
 
That's not really how it goes...
Would four 110 watt VHO's (totaling 440 watts) be as bright as one 400 watt metal halide? No.
A 400 watt would be brighter than even six 110 watt VHO's. For they are still only 110 watts each!
 
No it`s not how it goes but that`s the way they figure out WPG. I mean you`re using that example and yes you are right they would not be as bright but you would not get the coverage from 1- 400 watt light bulb in your tank as you would from 4- 100 watt light bulbs across the top. We are talking about TOTAL WATTAGE.
 
Dont be confused oldfishead. The way we figure out lighting is old school. But we still use it because we are talking about watts per gallon. I say old school because you need to think about how deep your tank is and what corals you have and other things involved. The simplest way to figure this out is total wattage / gallons of water = watts per gallon. You can then figure out what type of corals you can then have. Some People like to make people think they are so smart they try to confuse people. My intention is to keep it simple so we all understand. I dont need to prove to anyone how smart I am. I know I`m here to help. Maybe some other folks will add on. As I said dont be confused. Good Luck.
 
Would four 110 watt VHO's (totaling 440 watts) be as bright as one 400 watt metal halide? No.
A 400 watt would be brighter than even six 110 watt VHO's. For they are still only 110 watts each!


This is what's probably confusing you Oldfishhead. Stick with the 2+2=4. What kinda light you targeting? i'm thinking somethng in the 150w total range might work. PCs or T-5s maybe.

BTW, who's yelling? What defensive posture?
 
afishyonados said:
There you go again, defensive posture and yelling. I'm starting to worry about this.

If you have an issue with an individual, take it to private messages, do not hijack a post to do so.
Thanks.

As far as figuring out total watts per gallon Oldfishead, indeed, add all the watts together, divide by your tank size. When you feel comfortable with that, we can go into the rather confusing data and info about par and the different types of lighting that is available.
 
Lighting is not as simple as 25 + 25 = 50. Although we all really wish it would be. Watts is a measure of power consumption not light intensity. A 25W lamp will consume 25W of power over a specific time period. I dont know if its an hour or what that time period is. Two 25W bulbs will consume 25 X 2 or 50W of power over that time period.

This does not mean the total output of the two bulbs is twice that of a single bulb. The intensity will be higher with two bulbs but it wont nessicarly equal that of a single 50W bulb if we continue with our example.

Par is a measure of light intensity. Once you compare PAR output of the same type of bulb and two different wattages you also have to look at the output specitrum. IE the color of the light. You can have two bulbs but one is older than the other. As the bulb ages its PAR may not tail off as much as its desirable specitrum.

You go into even more issues when you look at differnt types of bulbs. Standard incadecent vs florecent vs high output florecent vs compact florecent vs Metal halide.

So the basic answer is 2 X 2 may = 4 but does not mean you will have the same results you would have if you used just one 4 to begin with. IE 4 X 1 = 4
 
Let me ask this question then. Say you have a 50 inch long tank. On each side you have a 25 watt bulb. On the bottom you have corals, plants, whatever. Would the two 25 watt bulbs on each side be better than the one 50 watt bulb in the middle?
 
I am sending you a PM aquarius so as not to confuse the OP further. Explanation forthcoming.
 
The 50 watt would provide more intensity. With the appropriate reflector, it could throw a 36" light pattern.
The 25 watts would still only be 25 watts.
 
Sorry to add to the confusion.
Oldfishead, austinsdad is correct. About 150 watts total light would be good for keeping most regularly available corals. Investigate the T-5 lights or the PC's.
 
I saw this, and figured I could add a question in with it (hope no one minds). Would 400 watts of metal halide be the same as 400 watts of PC? In the same aspect, would the 400 watts of VHO or T-5's all be the same? If I have a 120 gallon tank, and I want 8 WPG (I'm closer to 8.5, but I want to downsize the 2-400 watt metal halides for power bill reasons), can I get the same coral growth results with just T-5's or VHO's (I'm not too fond of PCs) and not worry about running the metal halides?

I currently have 2-400 watt 20k MH, 1-54 watt pure actinic T-5, 1-54 watt actinic plus T-5, and 2-39 watt pure actinic T-5's, with this rig, can I take out the 2 MH's, and add in 800 watts of T-5's or VHO's, and get the same results?
 
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