MH necessary?

[NightSpirit]

I was considering upgrading my lighting system to MH but was quite shocked at the pricing. Retro-fit isn't really an option if I can help it since I don't have a hood, and will likely electrocute myself in the process. Therefore the minimum I can find for a decent 60" MH canopy is $550, a little bit out of my price range.

What I do have is a 60" CSL 4x65 PC canopy with a reflector. Is it possible to retrofit this with metal halides?

If not, my other option is for ~$250 I can get another PC fixture.
This will give me a total of 8x65w or 520w for a 110g which = 4.72 w/g

Is this enough for most corals, or do I need to just cough it up and go for MH?

 

[fishfreek]

Lighting is the most expensive part of the reef setup. Dependign on the caonpy you might be able to retrofit it but you said above your not all that handy with electrical wiring. You wont be able to just slap a MH socket and bulb and wire it up to the existing PC ballast. MH requires a MH ballast thats ballanced with the wattage of the bulb. (IE a 150W MH will require a 150W MH ballast, a 250W MH bulb will require a 250W MH ballast).

Wiring these things up is more intimiadating than difficult. Your cheapest route would be to construct a canopy out of wood and install the MH reflectors and sockets in the canopy and remote locate the ballast. Install a few of your 65W PC bulbs in the same canopy and run them with actinic bulbs for suplemental lighting.

How many center braces does your tank have? That will somewhat govern how many MH bulbs your tank would look best with. Unlike florecent the MH bulbs WILL cast a shadow where the center brace is if its one of those plastic braces unless you put a bulb on either side of the brace to balance out the shadow effect.

 

[saberry]

I've read that because of the higher intensity, the 3-5 watt/gallon rule does not really apply to PC but I don't really know at what point it is necessary to get MH.

 

[malkore]

PC's are more intense than normal fluorescents...but it's only by like 15% on average. What I ususally do for FW plant setups is still use the wpg 'guidelines' for plants, but am aware that at 3wpg, I should have more than enuf light for any plants.

 

[fishfreek]

For a SW tank MH become more of a requirment depending upon what kinds of corals your looking to keep. Some corals should not be consitered unless you have very high output lighting over your system where as other corals should be shaded if such lighting exists over the tank.

The WPG rule of thumb is onliy good for flroecents. Toss it out the window when talking about MH.

 

[saberry]

PC's are more intense than normal fluorescents...but it's only by like 15% on average. What I ususally do for FW plant setups is still use the wpg 'guidelines' for plants, but am aware that at 3wpg, I should have more than enuf light for any plants.

A 55 watt PC is more intense than a 110 watt VHO.

BTW, I think the MH may also become necessary if the tank is 20" or deeper.

 

[NightSpirit]

Thanks everyone.
Tank is 24" x 18" x 60"

I would build my own canopy, but I'm as good with woodworking as I am with electricity, plus I have no tools. Also, the manufacturer of my stand/tank went out of business, so the only place that sells canopies in town doesn't stock mine anymore.

I realized what's wrong, my PC fixture is 1/2 as bright as it used to be. The thing is, I only bought it 5 months ago, and I've only been it using really for the past 3 months. Do you thing it's just the bulbs were junk and need replacing, or maybe somethings wrong with the ballast/something else?

If I bought MH lighting what would be better for my 110, to keep most corals?
1) 2x175 MH w/ actinic PCs
2) 2x275 MH w/ actinic PCs

I'm thinking of going with option 1, since the lights won't really be suspended too much from the top of the tank.

My tank has a center support, so a center bulb won't do too much, I don't think.

 

[fishfreek]

If the PC's are not as bright as they used to be then it could be due to saltcreep on the bulbs itself or it could be due to the bulb fadeoff that happens. Although 5 months is a bit short lived for a PC bulb. Maybe they where off brand.

TO keep most corals the better would be the brighter MH fixture. A center bulb will look awful with the center support. You need two bulbs both centered between the side of the tank and the center support.

 

[NightSpirit]

Thanks....it appears ACE hardware will cut everything for me for a couple of bucks, so I might just DIY on the canopy and go with a MH retro-fit system.

Is there anyway to make my CSL system retro-fit, or would I have to buy a new retro PC/VHO for the actinics as well? Anyone know of a retro-fit guide for idiots?

 

[NightSpirit]

Another question, would running the VHOs or PCs down the middle negate the need for two MH bulbs in the middle?

Or could I just put the more light intensive corals near the sides and the less light intensive corals near the middle?

It seems running two MHs in the middle would near double the cost of the setup.

 

[fishfreek]

You dont want the bulbs in the middle. You want the MH bulbs split even distance between the middle brace and the left and right side of the tank. The concept is to negate the shadow effect by having the bulb to the left of the center brace light the area that has a shadow being cast by the right bulb and the right bulb negates the shadow by the left bulb.

 

[HoopsGuru]

Metal Halide is a point light source, in that it distributes its light in a roughly 2'x2' area as opposed to a flourescent light that emits light from the whole length of the bulb (i.e. a 4' bulb will cover lighting over a 4' area).

If you put one MH in the center over the brace, the brace will likely disrupt and/or block a fair amount of the useful light that is the brightest right under the bulb. Not to mention, it will also have the shadow that won't look so good as others have stated. The only way to have it really look good and be effective would be to have 2 MH (1 centered between the left side and center brace, the other between the right side and the center brace). This will create the most useful light and keep shadowed areas to a minimum (good place for mushrooms, etc.).

Your stuck in a tough spot! If you add another PC fixture to save money remember that is more electricity used probably than going MH. Also included is multiple bulb replacements every 8-12 months (I have never made it even close to 12 months without a severe loss in intensity :? ). It becomes pretty much a choice of pay a lot at once, or a little over a long time. Your budget should dictate which is more reasonable when combined with what you want to keep.

Seeing that MH is an expensive purchase for you(and for me....I still only have 1 instead of the 2 I need!), I doubt that you are going to be purchasing and keeping high light requiring SPS frags and clams for $35-$85+ a pop so I would honestly go with 2x175w MH or maybe 2x250w MH to be able to keep a wide variety of corals. If you are "wood-workingly impaired" (a new word, don't check Webster's)....you could also consider the use of pendants that hang over your tank (but normally cost a bit more). Each 175w or 250w retro should cost around $190.00 (total for both assume $400) including everything you need to mount into the canopy. I would go with 14k bulbs and skip having to supplement with any kind of actinic for color (so maybe you could sell your existing PC unit to offset the cost a bit?). I like and use Coralvue...have also heard good things about Hamilton but I have no direct experience. A fan may be necessary to get air moving through the canopy, but I'm sure a clip on variety could suffice or simply having the back out of the canopy and a few vent holes elsewhere. You have a lot of water volume to dissipate heat (ultimately will depend on the ambient temp of the room, etc.)

A lot to digest, but there are pros and cons to everything. Maybe this gives you more to chew on and decide which path is the best for you.

 

[NightSpirit]

Thanks, I'll keep you all informed about what I do.

Right now I'm in the process of a DIY canopy, and when that gets done I'll examine the lighting options.

I might do something like 1x175 on each side and use 4 of my 65w PCs in the middle, and maybe two VHO actinics running down, one on each side.

 

[HoopsGuru]

Good luck! I think you will find that with the MH, you will not need to add much extra lighting unless you want to (for say, a dusk/dawn effect before the MH come on). They effectively cover a 2'x2' square, but this doesn't mean that no light travels outside this area. The coverage area is just where you are guaranteed to have the most intensity of this point light source. With 5ft of tank, a MH on each side of the brace should perform pretty well in my opinion. It's all confusing, as you get to see pics of more tanks and find more information....it will all start to come together.