Lighting, Heat and Ventilation
Hi, I'm a newbie to the Saltwater arena and have purchased an Oceanic 72 Gallon Bow Front RR, with canopy. I also purchased the JBJ power compact fixture 48" 65W*4, Formosa -DX. Yes it has a hood. My concern is the heat created in the canopy. The fixture has fans, but there is little room on the ends for air to circulate.  The sides of the canopy (Flexible plastic) do get warm to the touch, but not intolerable. The canopy is open in the back, but that is the only source of air. I have had  suggestions of cutting holes in the end of the canopy, but I'm concerned about damaging it and it's aesthetic value.
<Hmmmm, if the unit has fans and was designed for this use, not to worry for it's sake. If heat is an issue, and it well may be, then additional fans, perhaps a raised or suspended fixture may be a better route for you. Look into additional fans and also brackets for supporting your fixture above the tank rim online at one of our sponsors like Foster and Smith. JBJ would be the place to start.>
My concern is the heat build up and potential damage to bulbs and fixture. Retrofits really are not an option as the top of the canopy will not support them.
<Brackets hold fixture on aquarium rim for support. They make then for 48" fixtures/tanks.  Also, use eggcrate instead of the plastic stuff that came with your tank to increase ventilation.>
Any suggestions? My plan is to have corals as well as fish. I know I could eliminate the canopy, but would rather not.
Thanks in advance from a "new comer". John
<Well, there are several ways. You will find that aesthetics combined with proper and needed function has a price. Poor function is not an option and that's what you have now. There is no doubt that if heat is a problem, something will have to give.   The degree you choose to mix these is up to you and your situation/taste/pocketbook.  Also consider your locale, if your summer weather is hot and you don't have AC, best to open things up and maybe think of a chiller!  Best to start with simple ventilation first!  Craig>

Lighting Fan
Help Please:
<No problem Steve!>
My 125 gallon reef tank is running 84 degrees. I have ordered 2 ice cap 4 inch fans to cool the canopy lighting power compact 72496 retro. Do you recommend that the fans blow into the canopy or out from the canopy? Also, do you recommend that the fans be installed inside the canopy or outside the canopy?
<Where they are mounted, inside or out is a matter of taste and where they fit best. Most are mounted inside with the finger guard on the outside. Mount one exhausting and one blowing.>
I also ordered an ice cap 4 inch fan to cool the lighting for the ecosystem filter lighting. Should the fans blow inside towards the lighting or blow out from the lighting? Thanks, Steve
<Mount it exhausting (blowing out). The incoming cool air will fill the hood from wherever air can fill it. Blowing in is less efficient and cools less. Should keep you cooled a few degrees. Craig>

Lighting
I have a lighting question for you. I just bought a custom 120 (used) with no lights. I currently have a FOWLR 75 gallon with only 30 watts of light. The LR has some coralline algae and seems to be doing fine. I really didn't understand anything about lighting until the last few weeks. I have been doing a lot of research. I have read your book The Conscientious Marine Aquarist but still am not sure what to do. Firstly I was bound and determined to go with MH. After learning how hot they get and the cost I decided to move on to another option.
<All lighting generates heat, MH's no more than others.
<<... no... wrong... RMF... Varying technologies produce a very wide/disparate amount of heat. None more than MH>>
 And not that much more expensive initially compared to other lighting options that give the same intensity. One 175 watt MH will cover a 2' x 2' x 2' area pretty completely. To get the same sort of coverage and intensity would require 4 55 watt PC's or 4 75 watt VHO's. MH lamps will go at least one year before replacement is needed, some up to three years. VHO's need replaced every 6-9 months and PC's every 9 months to one year. IN the end, MH's are more cost effective.>
Next I was going to use VHO, which also seems to create some heat. Then I decided to just fill the entire hood with fluorescents T-12. Now after reading more you seem to be a real fan of compact fluorescents. What I really would like to do is take your advice directly. The tank is going to be a FOWLR for a little while longer. I would really like to get some good things growing on my rocks before I change over to reef. The lights will be about 2 inches above the water and from the top of the water to the bottom of the tank is 23 1/2". Please let me know also if you think the lights should lay on a piece of glass or if it will be OK for the lights to just sit directly over the water on the 2 glass beams.
<You have to follow the manufacturer's recommendation on this point. Some fixtures are ok, other not.>
So what is your professional recommendation. I was thinking somewhere along the lines of 440 watts of light with full spectrum and actinic. Thank you.
<Any specific recommendation depends on what corals you wish to keep. What is needed for same Yellow Porites would kill many LPS. Decide on this and then look over the FAQ's for any specific recommendations. -Steven Pro>

Lights & Heaters
Hi Bob and or Crew: A couple quick questions in regard to lights and heaters. First with heaters I currently have two Visitherm 300 Watt heaters in a 110G reef tank which I would like to move to the sump. Is mounting horizontally a problem with these heaters?
<I have never had a problem mounting them this way.>
Is this too much wattage for a 110?
<maybe slightly more than needed, but they are thermostatically controlled and will not overheat your water. They merely have extra capacity to heat your water if need be.>
Would I be better off with two Jager-Jager 200 or 250 Watt (I like the 2MM thickness especially in a sump)?
<They are a better product.>
Now on to lighting, I am about to buy a Giesemann 2x250 watt metal halide with actinic PCs which I will hang about a foot above the water surface. This light uses the double ended metal halide bulbs which create a very brilliant light but also seem to throw more heat than the common socket metal halide. Any info in regard to these lights and/or bulbs?
<I have not seen any comparative info on difference in heat output. These double ended units put out more light than the same wattage single ended lamps. -Steven Pro>

Light vs. Heat
Anthony
<Anthony is off at the Backer Trade Show. You get Steven this morning.>
I just purchased a 260 watt power compact, with fan, for my 110 gallon tank. The unit is raised about 1 inch from the glass which is all the room that I have under the canopy. I noticed that my tank's temperature has risen by 2 degrees in the six hours that the light unit is on. Will this cause any problems for the fish
<You do not want the temperature to fluctuate so you may have to use your heaters to maintain a warmer temperature as long as the maximum temperature is 82 or below.>
and if so how can I help to dissipate the heat.
<The proper use of fans and vents is the easiest way. You want the light fan to be able to blow the hot air outside of the canopy. Else, purchase a second fan to do so and mount it on the back of your canopy.>
The canopy is solid on top with airflow coming only from the rear. Thanks as usual. Joe
<You are welcome. -Steven Pro>

Light vs. Heat II
Steven,
A continuation of my heating problem..
I kept my hood open to see if the power compact light was causing the heating problem. (the house temperature was about 79-80* due to a current heat wave)
<Pittsburgh has hit 86F today. Strange weather indeed.>
The water has not heated up any further so I think that the use of a fan in the hood might be the answer. Which way should the air flow be directed; exhaust or inflow?
<Exhaust>
The water temperature in my 110 gallon tank is at 83* and has not gone down in spite of air-conditioning the house overnight to 75. The quarantine tank on the other hand only raised to 80* in the heat but went down overnight to 77* and is being controlled by the heater. I am assuming that the temperature fluctuation in the 10 gallon is a lot faster than in a 110.
<Correct>
How should I go about lowering the main tanks temp or do I allow the cooler house temp to control it and if so how long should I expect it to take. Conversely, it heated up quickly.
<If you keep your house at 75, I would think using an exhaust fan would bring the big tank down to 77 in another day or so.>
Should I look into the use of a chiller or do you think that the use of the exhaust fan in the hood will control most of the heat source?
<If you usually run your AC, I would not worry about the chiller. Even if you keep your house at a modest 78, you should be able to keep the tank at 80.>
Thanks again.
<A couple more general points. Minimize the usage of powerheads. Much better to use external mounted pumps which dissipate their heat into the room and not into your tank. -Steven Pro>

Lighting (concerns re heat production, elimination)
Hi Mr. Fenner,
I have a question concerning lighting. My saltwater tank is 60" long x 30" high x 16" deep. The problem is at the top, the middle third has a glass brace across it that is 5/8" thick ( same as the tank sides).
<A good idea>
How badly will this affect the tank concerning the lighting, since it is already a deeper then average tank,
<Actually, the depth of this length/run and volume is a few inches less than "average">
if I want to eventually make it into a reef tank? I know have a FOWLR. I cannot put anything that will heat up a lot. (The top along with the sides are completely enclosed in a custom built cabinet, and it is a see-through to both sides, and already on hot days I have to keep the top door open for heat dissipation, even though my current lighting is way under in terms of sufficient lighting which consists of two 48" fluorescents.) 
<Good description>
I am currently trying to figure something out to vent the enclosure without any light straying out .
<Perhaps some openings on the top with a "light barrier" to allow air circulation, block light... or drilling through the tank, running a clear pipe up through the bottom with cool air... or... >
The cabinet is in the kitchen/living room wall, and stray light will not be convenient. A thought: the current enclosure has particle board on the top ( hidden by molding around the edge), if I cut out a big section, and replace it with something heat conductive, such as aluminum, or such , do you think this will make a difference to dissipate the heat up, and out of the enclosure, instead of a fan or such, or will this not make enough of a difference to merit the trouble of the modification? 
<Interesting... but don't think this would make much difference>
In other words, does passive heat dissipation in this way, work as well as an active design? 
Thanks, Greg
<Consider the "chimney" approach with or w/o muffin fans to move air over the top and not to worry about the changes in light (some loss of intensity, phase shifting... not too appreciable). Bob Fenner>