MH lights raising water temp

Baseball bats, shotguns and hand grenades. They take care of many things. Just watch out for collateral damage.
I agree with you on the aesthetics of the hood. It looks better closer to the tank. My lights are 10 - 12 inches away from the top of the tank and now I have to take my canopy down and stain all the spots I didn't think I would see originally Even so, 500 watts of metal halides on a 90 gallon should be more than enough. This is a TALL tank and if you absolutely have to have tons of intense light craving corals, put them closer to the top of the tank.
I have to be careful right now to acclimate my sponges on my live rock so they do not burn/bleach out. [glow=red,2,300]Intense Lighting[/glow]
Food for thought
Jim

 

There are several advantages to using a glass/plexiglass shield between MH bulbs and your tank.

1. By enclosing your lights and using a protective glass/plexiglass shield you can effectively create a wind tunnel, so to speak, by placing a fan on either end, one for intake and one for exhaust. This will exhaust the heat away before it can come into contact with the water's surface.

2. Running your MH bulbs without a protective shield runs the risk of a tiny drop of water coming into contact with your hot bulbs causing the bulb to explode. Not only do you need to purchase a new bulb at this point but now you are faced with the challenging task of cleaning broken glass from your tank.

3. HQI bulbs require a tempered glass shield to filter UV rays.

4. Sure, a glass or plexiglass shield might filter some of the light thus reducing the output to some degree. But by using the method listed above you can effectively lower your lights closer to the water's surface taking better advantage of your MH bulb's output without fear of splashing the bulbs, and maintaing better heat exhaust and temp control. The output from metal halides degrades VERY quickly when distance is a factor. A difference of a couple inches in height from the water's surface will result in much more lumens for your tank.

Many people run metal halides without protective shields and never have any problems, but I would recommend against it for the reasons listed above. With the amount of money/time/effort we spend on our tanks, why not try to optimize our lighting setups for maximum efficiency and safety?

Just my 2 cents.
Hope this helps.

 

Good points FO. I'm one of those who doesn't have any glass between my lights and the water surface. I do clean my 175w MH bulbs once every two weeks. I only have glass on the back half of the tank and since removing the front piece of glass my water quality is improved due to better gas exchange. It's always give and take, eh?

 

I have the plexiglass as part of the canopy, in front and behind the canopy is open top ;D

 

If your using an open back and fans, your not using the fans effectively. You should try to enclose the back of the canopy, so the cold air is sucked in one side (larger in hole, then out) and spit out the other. Don't use a fan pushing, always use them pulling, and definitly don't try to push and pull. One fan will always burn out much quicker if you do so. All my canopies/tanks have always been uncoverred, as far as glass tops go, and always have just one fan pulling. My 2x 30g tanks have 2x 55 pc each and 1x 150 HQI each. I get zero flucuation of my temps, unless we're having a sizeable heat wave.

If the halides are heating the room up, no fans in the world will help in your canopy, unless they're blowing directly across the water surface (evaperative cooling). E.C. is an option you should try as well. Have a fan blow across your sump, when the halides turn on.

 

Also, the plexi and tempered glass not only cut down amount of light transmission, they also cut down certain spectrums. No good IMO.

 

My fans arent in the sides of my canopy , there in the top front of my canopy so it pulls cool air from the back across the bulbs and then out the top, I thought this would be the most effective place to put the fans since heat rises. I raised my canopy a little last night and it still didnt help anything , I turned the lights on at 11:30 and at 2:30 it had got back up to 83. So its rising about 1 degree an hour, I guess ill go buy 2 more fans and hope it works.

 

Try to close of the rear to only have a bit more openning, then the fans total area. I've found having fans on the top don't really help any better, then having them on the sides. The fans seem to last longer when place upright, rather then on their sides. My old corner tank had top mounted fans and I had to replace them twice as much as the tank with them on the sides.

try blowing across the water surface, it may solve your heat problem, but will increase your top off'ing.

 

u could raise them to about 10" like mine, my tank never goes over 78

 

I wish I could raise it to 10 inches but my canopy is as high as it can go, Id have to build another canopy. If I would have known these MH lights would be such a headache I would have went with VHO's .I already have over 300 bucks in these things and I cant even sit back and enjoy them, and on top of that it looks like I have a tanning bed in my living room when the lights are on. Ok had to vent a little , feelin better now lol