250W MH over a 29? Good idea?

[Jrsydevi1]

I know its probably overkill.. but i got a good deal on the retro kit.. Right now i have a DIY hood with 2x55 PC's...

This is my first venture into the world of metal halides..

Question is.. is there such a thing as TOO much light?

My PC's are about 5 inches from the water surface now and are separated from it by a glass cover.. One 4" Radio Shack fan blowing in.. The hood is vented by a 3/4 inch slot running its length on the top.

I could always redesign the hood to raise it more. Or remove the PC's altogether..

Will the 250 emit so much heat as to shatter the glass cover? I already bought the 250 kit, so I'm gonna use it one way or another..

What would you do?


Also.. I havent purchased a bulb yet... the Ballast is pulse type.. which bulb/combo would you use?

 

[Anonymous]

It's only overkill if your keeping lower light corals, I had a 250w on a 29g too, same lights on a 20g long, and a 10g before that.


You'll probably need the glass cover removed, so you wont trap heat in the tank

 

[Anonymous]

remove the glass cover altogether-it just blocks light transmission, and helps the tank to hold in heat :wink:

evaporation will enable you to add kalkvasser, anyway

the 250 on the 29 will let you keep just about any of the higher light level loving inverts

your only major worry would be heat-and if the canopy is fanned/vented properly, the halide should not be that much of a contributing factor

hth

 

[Jrsydevi1]

The tank is 2 yrs old.. and all I have in it is some nice Gulf-View LR, one clownfish, a thriving colony of Green star Polyps, and a tiny frag of button polyps.. Do you think the GSP will be adversely affected?

One of my PC's is actinic.. what do u think about the Iwasaki 6500k MH as a bulb choice?

Also.. should I raise the hood?

 

[wizardgus]

I had the same setup when I had a 29g. I would definitely lose the glass, go with eggcrate for a top. Then I suspended mine from the ceiling about 8" off the water, this gave me very little heat issues. You won't get perfect coverage as max. effective spread is 24" and your tank is 30". I used 2X55PC for supplement and that way I had my softies outside the Halides footprint. If you like the color of the 6,500 is the only question. I used a Radium, but I was firing it with an electronic HQI ballast. I wouldn't advise on that bulb with a standard ballast though, reports have been pretty spotty on results. HTH

 

[buff1]

5" from the water is too close for MH. I would shoot for more like 8-10" This will keep the heat down and help cut down on salt build up on the light.

 

[Anonymous]

I have a 29g with two 250w HQI pendants, though they're only on simultaneously for an hour a day (I have one go on in the morning, then the other goes on for an hour, then the first turns off, to slightly simulate the sun moving across the sky). I also have a single VHO actinic bulb.

My tank has gulf-view rock + some zoanthids, LPS, and SPS, and halimeda, and everybody seems happy.

 

[Anonymous]

Go for it. Evaporation is probably the biggest hassle you can keep it far enough above the water to make the heat buildup minimal. FWIW I have a 250watt Halide Pendant I had over a 18 gallon for about a week just experimenting and I think it would be awesome for say a small clam or sps tank. I am planning to get a canopy with some fans built using this reflector/socket and moving my LTAnemone into a 18 gallon by himself once he gets a tad larger (won't take long I think).

Also check out the madness of Lunchbucket's nano site. He has a 250 or maybe even 400 watt over a 20 gallon custom nano.

www.lunchbucket.org

HTH

 

[ScottC]

I had a 250w 10k MH and 2x55w actinics hanging from the ceiling over a 30g for years. I had heat issues until I added a 15g rubbermaid container next to the sump with lots of air exposure. It evaporated like crazy (1.5g a day), but everything in the tank LOVED the intense light. Go for it