MH Lighting

[Mr_Cool]

I have 2 questions about MH lighting (which I really know nothing about).
Maybe someone can help me out.

First: I've seen pendants and retrofit kits. The pendants all seem to have a glass UV shield or something, whereas the retrofits don't. Is it o'kay to let the bulb be open to the water below? Something just does't seem right about that!

Second: How much heat will one MH bulb generate in an enclosed canopy? I'm sure I'd need a fan in there, or at least some type of venting. But, what type of increase in water temp. can be expected?

I'm sure I have other questions I don't even know how to start. (Like how do 150W or 250W MH compare to t-5's?) If you can point me in the right direction to find some answers, I'd appreciate it.

[urban79]

well retrofits are just mostly tansformer kit and socket. Plus you shouldnt have you light so close that water hit them. glass or no glass. MH get hot, real hot. If water hits you bulb after its been on for while. Its going to be in your tank. With the temp You should just see. You will need vent and a fan. But how much you will just have to see. Like mine I have 2 250watts MH. Its open on top and I have 2 fan on it. But mostly Just one fan is on all the time. MH are nothen like T-5s you really can compare the two. MH are a very bright light. You cant look at it when its on. its Like looking in the sun. T-5s are just soft light that just let a little light.Thats why you need the watts per gallon. But there are alot of pos and cons to lighting. Alot of ppl dont light MH and some PPl love them(like me) so ppl love flourcents lighting. Just up to you and what your trying to go for. Plus MH dont go off the watts per gallon rule. 150w and 250w are just mostly for height of tank and how much light you want you floor to get.. 150 watt Will light up your tank but not so much on the floor. Which a 250 will give you alot of light on the floor.
Hope this help a little

[cpreefguy]

Also, double ended halides need the UV glass shield or else all of your corals will die

[MattK]

Also, double ended halides need the UV glass shield or else all of your corals will die

Wow, I didn't know that, of course there's a lot I don't know. Learn something new everyday.

[caferacermike]

I can tell you that even with the shield I don't like my arm being under my 150 HQI De bulbs for longer than a minute, it'll tan and burn you quick. Anyone know if the glass has to be tempered? I have heard that any glass will repel UV light. I'm wondering as I am going to be gutting a fixture to accept 2x 250 hqi to replace my current 2x 150hqi. When I do this I will need to get glass cut about an inch longer.

Screw in bulbs don't need the extra glass as the bulb is designed in a way that the UV can't get at you or your tank. Something about then being double walled. It is advisable to have a shield in place with screw in bulbs to protect them from splash, as stated they will blow instantaneous when exposed to cool water.

[alton]

(Heat Issue #2)On my 200 I run 1 fan 24-7 and the other runs when my lights are on and cut off when the lights do. I do not have any heating issues. I run 2-250w MH, 1- 160w VHO, and 4-54w T5HO. Also with running one fan 24-7 I do not get a moisture build up in the canopy.

[Louie3]

So how do Power compacts compete vrs. Regular flourscent lighting. I would love to have MH running in my tank but down here this south in Texas, your realy gunna have a heat issue. I was running or i should say test driving (2) 250 halides on my 55g softie and had major heat problems, even in a well ventalied room with fan and the ac at 74-76. So I was wondering if I would get another heat problem running 6-8 power compacts with the built in fans. and what type of color combo?

[hobogato]

mike - if you are thinking of running MH lights on that 75 corner, then you can not put them in the canopy i built for you. it is much too short. the only option with that canopy would be to open up the top and put a pendant over the opening. that canopy was made to house PC or T5 only. MH would be WAY too close to the water, and you would boil your tank as well as run a very high risk of splashing the bulbs and having them blow.

[Mr_Cool]

Ace - I know MH lights could not go in that canopy if it were enclosed. I was thinking of maybe cutting an opening to house a pendant, and then surrounding the pendant again. (Does that make sense?) The pendant would sit up above the original top of the canopy inside of an enclosure that would be a truncated pyramid. So, the whole canopy would still be enclosed, but the MH light would be higher than the original 5-6 inches you built. This way I could keep the PC lights for the actinic, and still be very well lit. (BTW, the tank is up and running. Everything looks pretty good. I'll post a pic or two once I get the PC lights mounted inside the canopy. The MH conversion may be a while.)

So anyway, how much above the water does the MH bulb need to be?

[cpreefguy]

Ace built me a custom canopy like that. It fits perfectly on top of my tank, and he cut out the middle so that my 36x11" fixture sits on top of it, about 9" off of the water.

[KyleV]

sorry trying to start a new topic and can't delete this.