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Re: [APD] Lighting question

A T5 is the same technology as the 55 watt PC. It's the same bulb diameter, ballast, etc.. The only diff is the T5 tube is not bent in half. The diffs n wattage are negligible and you can run either on a ballast made for the other. Anyone that thinks there's big diff between the bulbs, beyond shape, needs to have their lights examined. ;-)
An advantage of the shape of T5s is that they more easily retro into office lights that were made originally for T12 orr T8 bulbs.
MHs and high output fluoresecents have clsoe tothe same efficiency so will give the same amount of light, watt for watt, give or take a few. The main diff is how the light is broadcast. An MH emits light from a very short arc, so most fo the light reaching a surface is coming from the same direction. A fluorescent emits from the entire surface of the tube and light reaching a surface is coming form many diff directions, so shadows are softened and the lighting much more diffuse. For this reason you have diffs in aiming light with two types.
VHOs are an older technology using basically standard fluorescents that are beefed up to withstand being driven much harder to emit more light.  They are good for cramming a lot of light in a small space, which is an issue for some reef tanks but not for planted tanks, generally. They tend to be shorter lived and less efficient.
Like Audio loudspeakers, most folks think the ones they bought are the best.
* * * * * * * * * * * It's new; it's fun; it's the New England Aquatic Plant Society NEAPS, is a newly formed organization interested in aquarium flora and fauna. http://www.ne-aquaticplants.com/ 

----- Original Message ----
From: Billionzz at aol_com
To: aquatic-plants at actwin_com
Sent: Thursday, January 26, 2006 3:07:03 PM
Subject: [APD] Lighting question

First I would like to thank everyone on this list for all of the help and  
information I have received over the past few years.

I now have successful planted tanks that have great growth and little algae  
problems as long as I keep up with the maintenance side of things.

While planted tanks are my favorite I started a small reef tank and I'm  
trying to get a straight answer on lighting. This is next to impossible on  the 
reef forums, they all have there different camps, (MH's / T5's / VHO and a  few 

On the freshwater side a lot of information that was thought to be fact  
turned out not to be and I'm sure it's that way with reef tanks also but I would  
guess that there is a lot more myths with reef tanks than with planted  tanks.

I was hoping that maybe I could get some opinions over here since this list  
has always seemed to have the must knowledge of any of the forums I 
participate  in. The others forums are good and I am glad they are available but 
sometimes it  good to look at things from another point of view.

My question on lighting is with PC's and T5's, I'm not really interested in  

I was wanting to know if there is a way to compare the two, can they be  
compared by watts per gallon? For example on the reef sites they told me that  
104w of T5 lighting is more light than 192w of PC lighting, does this sound  

In general there aren't to many people that like PC lighting but I  really 
can't get a good answer as to why. One other thing they always say is  that you 
have to change the PC bulbs after 9 months because of a light spectrum  
changes and it will cause algae if you keep the same bulb in. That  doesn't make 
sense to me since I have ran PC's on my planted tanks way  longer than that 
without any problems.

I know this is a freshwater forum but I value the opinions here and was  
hoping to get some input on this topic.
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