hey Guess what ? Another lighting question !

[vermonter310]

Okay, I've been reading about lighting for weeks now.....and I am now more confused than I was when I started. As I research corals I find most sites rate them on how much light they need, except they only say low , medium or high lighting requirements(or combinations. ie. low to medium). WHAT DOES THAT MEAN ??? Ahhhhhh.........Drives me crazy. Most people seem to recommend Metal Halide lighting. Usually one or two 175 watt or 250's. so my question and one i can't seem to get an answer to is what is the difference in say 350 watts of metal halide and 350 watts of VHO or power compact. As it relates to the corals that is. I am aware they provide different looking light. This all started as a FOWLR and now that I've been researching I 'm sure I'll want some corals and inverts, probably would like a clam as well. As I'm sure is the same as most I don't have a bottomless wallet. I am very seriously considering a 440 watt 4-48" tube VHO kit from Hellolights.com ($161.00)and building my own canopy. I'm not crazy about metal halides because of the cost heat and space the take up and the (need ?) to add additional NO or VHO actinic lighting so I've been leaning toward VHO. This will be over a standard All-glass 75 (or a 55 if I can't convince the wife the 75's the way to go.) So to boil things down, how many watts of VHO are required for corals with "high" lighting requirments or is VHO just not enough ?

Thanks

[saltyfishboy]

Different types of lighting do different things. For example, Metal halide bulbs are very intence...but the light from them wont penetrate the water very deep. On the other hand PC lightbulbs have a deep penetration.

Corals need to have atleast 3-5 watts per gallon. This is the same for whatever type of lighting you have. If you get the VHO lights you will have 440/75 = 5.88 watts per gallon. That is what I would consider high.

On a personal note. I have never used VHO lighting. But I am pretty darn happy with my PC lights.

Hope this helped.

[Anemoneman]

Metal halide bulbs are very intence...but the light from them wont penetrate the water very deep. On the other hand PC lightbulbs have a deep penetration.

Would you post the resources you base that claim on? I haven't had the same experience.

Mark

[michealprater]

im also curious on that. I dont see why one type of lighting would penitrate deeper that the other.

[loganj]

Although I think most corals can be grown under PC/VHO lighting, I have to disagree with the statement that MH doesn't penetrate the water as well as other types of lighting. Bear in mind that I have done no scientific testing on this... The MH light is concentrated in a smaller area thus it seems that it would have a higher penetration than other types of lighting. JMHO.
Logan J

[Bang Guy]

logan is right. The closer to a point source of light, the deeper the light can penetrate water. So... HID lighting penetrates further followed by PC and then VHO. The less of a point source the more area can be covered and the more even the coverage. With electronic ballasts, they all produce about the same amount of light per watt of input power.