Light shattered my glass!!

[pendergraft2111]

Ok so here is what happened. I have had a ton of freshwater tanks and have now started my first Saltwater tank. I have been doing a ton of research and my wife wants me to put coral in the tank so Metal Halide...right? I bought two for my 75gallon DAS tank. It has a built-on 2.5 inch canopy with covers so I had to customize the lamps to fit under it. I bought 1/4inch galss to put under the bulbs to keep them safe. I wired up the ballast under the tank turned on the lights and WOW they were bright and beautiful. The live rock looked great and the damsel I am using for "cycling" came out and looked like they where loving it. I am sitting there marveling at what my wallet is crying about...lol and then BOOM and CRASH... the galss I bought shatters and falls into the tank. I immediatly turned them of and I am slightly scare to turn them on without some sort of cover. Right now all I have are 2 three foot long 50/50 bulbs on. Excuse my nube but the best I can figure is one bulb is 300watts(blue for some reason) and the other is 400watts. I bought them second hand and as I am sure most of you know money is getting tight on this project...any ideas/suggestions?... I bought some fans but have not wired them up yet... I am at a loss and broke for at least a month. Any help would be greatly appreciated... Thanks in advance.

 

[Gti_Leo]

how close to the glass did you place the bulbs. 700watts of MH give off a llooootttttt of heat. a slight splash from the cooler water and that should shatter.
best thing to do is keep the MH lights atleast 6 inches from the water to avoid any splashing and also to try and keep some of the heat from the water

 

[pendergraft2111]

Is there any good alternative to the metal halides? Are both of them too much/too little for 75gallons? Do I need a fan on them or is just moving them farther away sufficient?...sorry so many questions

 

[thincat]

MH are great, but they put out a ton of heat. Raising them up is one alternative. The other is to switch to a T-5 HO unit with at least 4 bulbs. Not as much light but not so much heat either. Fans are a good idea. From what I can tell you had your MH less then 2 1/2" from the water...much to close.

 

[Gti_Leo]

i beg to differ on the light output t5s produce the more lumens per watt, but the light is spread out the entire length of the bulb unlike the MH that directs all its lumens of light at one area. which is why they are so good, you can direct the light right at a high light coral or anemone which you can't do with a T5 unless you get individule reflectors and aim them

my personal preferance is t5s but they also require more bulbs then the MH to achieve the same wattage and output. to equal the same light as a 250watt MH you'll need 5 4 foot lamps.

another advantage to T5s is they last longer and they don't lose as much light output over their lifetime as MH. at 40% of its total life a 400watt MH will drop from 36000 lumens of light to 23000 while a 6 lamp t5 with output 30000 lumens and at 40% have 29000 lumens of output


http://www.day-britecanada.com/showdoc.aspx?rid=SHE Fluorescent High Bay.pdf.pdf

this is a florecent 4 foot light fixture that they classify as a highbay, which in most industreal and comercial building are now being retro fitted in to replace the 400 watt MH. equal light output at a lower wattage therefore you're electrical bill will not be through the roof. if you have a canopy over your aquarium you won't even see the fixture, just screw it to the top and place whatever bulbs you see fit. my opinnion is 3 or 4 actinic and the rest 12000k or if you like the blue 14 or 20000k

or this is a much narrower fixture that can fit 8 T5HOs ing a rounded more direct unit

http://www.day-britecanada.com/showdoc.aspx?rid=259 Alumabay Brochure.pdf

 

[pendergraft2111]

This is a LOT of good info, Thank you to all of you. Looks like the t5ho's are for me. I really want to have everything contained. Spent like half the day cutting down those fixtures to make them fit... oh well rookie mistake...

 

[mr_X]

i think you are mistaken about the 400 and 300 watt halides. metal halides don't come in 300 watts. it's 70, 150, 250, 400, or 1000.

i would use a minimum of 6 t-5 HO lamps over a 75 gallon tank, but preferably 8, and i would also use quality lamps such as ATI or giesemann.