heat concerns for canopy

[ddold]

I just finished setting up an Oceanic 144g half circle tank ... wonderful views inside and I can't wait for it to cycle so we can move the inhabitants in to their new home.

Once concern I have is the heat generated by the lighting ... I've got 3 250w MH, and as anyone who has an Oceanic knows, the plastic for the hood and tank top isn't going to make the grade structurally. I built a high temp pvc framework to hold the lights as far off the water as possible and I want to use a piece of plywood to strengthen my light scaffolding, but should I be concerned about a piece of wood in contact with that much heat? The lights come on in a staggered pattern so all three are only on together for about 4 hours, but it still gets hot.

Fans are on order to take some of the heat out/blow cool air in, and I'm going to cover all the plastic inside the hood with high temp heat foil that motorcyclists use inside their bike's fairings to prevent their exhaust pipes burning a hole in the plastic, but Im just concerned about my plywood plans.

 

[minibowmatt]

when you say High heat PVC what are you referring to? CPVC?

 

[Len]

Any way to get a metal or nylon spacer in between the wood and lights? A half inch will do wonders. I used to have my 400W directly mounted to pine, and it did char it a bit (no fires though, thank goodness )

 

[ddold]

A spacer could be fitted between the lights, especially if it'd prevent forest fires. I wish the hood were taller, but I've got to make due with the height that's there.

On the PVC front, I explained what I was planning to the orange apron dude and this is the piping he directed me towards. I can't remember the heat rating, but he said as long as I wasn't setting it alight directly, it should hold up.

Maybe I should just ditch the PVC entirely and go with plywood supported by 1x2"s and it'd give me that extra 1/2" the PVC is taking in the height as well.

 

[cindre2000]

What I did with my light was to suspend it with some screws. I build the hood out of 10" by 1" white pine and then I picked up some plumbing brackets at lowes. By running the screws through the holes and then through the hood (held with knuts) The light is a good 2-3" off the wood. When I add the fan, my hood will not even get warm.

 

[Anonymous]

Looks pretty handy. Nice job

Louey

 

[cindre2000]

Thanks, I still have to paint the inside white and I am thinking of replacing the ballasts in t5 light strips to HO ballasts.

Hopefully this summer I will be able to finish the tank for real and get my surges up and running.

 

[ddold]

Very nice ... I am going the same route as well, home made spacers and a couple of fans should do the trick.

 

[Dagwood]

Ddold,

I have been looking at the 144 gallon tank to purchase (really been researching my setup). I am very interested in your lighting setup. How's it working for you and could you send me some pictures?

Thank-you,

Darren Crownover

[email protected]

 

[ddold]

Sorry, I havent been checking the forums for a few days ... I ended up using a piece of 1/2" thick high temp acrylic, cut in a half circle 1/2" smaller than the radius of the hood itself so that the support beams for the hood sit snug against it. I cut out access holes where the two side panels are so I can get in to feed and other minor chores. For major work, the apparatus is supended on five 2" thick acrylic legs, so it's easy to just lift it up and stand it on the backside of the legs giving full access to the tank.

The acrylic is rated up to 300 degrees, but I also added some sticky heat shield to the inside parts of the tank that are exposed to the light, and to the mounting board and it's legs. It is stuff I used to use when I raced motorcycles, and it's designed to stick to the inside of race bike fairings to protect them where an exhaust pipe rubs against it directly. Very good heat resistance, and as an added bonus it is somewhat reflective. I also added two of the 3" IceCap fans, one in each of those end panels on the backside of the hood. The 3" fits absolutely perfectly in between the support structures for the hood, and I've got both of them blowing in along the radius of the hood so it seems to make a good swirl and has really helped with the temps.

I'll post some pics later tonight when I have to go in a due some maintenance anyway. All in all, I'm pleased with the results. It's been running for a week or two now with no heat problems. The only drag is that the lights are fairly close to the tank glass, but without making an entire new hood, there's no getting around that. The tank is deep enough that it might actually turn out to be nice having the lights a bit closer to the waters surface, and with the heat wrap and the fans going it isn't hurting the tank at all to have them there.

 

[ddold]

Sorry for the delay ... child maintenance taking priority over tank maintenance

Here is the light stand from the top

 

[ddold]

from the side ... the bulbs sit 3" off the glass, 4" off the water

 

[ddold]

the lighting arrangement itself ... the left light comes on first, 10k 250w bulb, and runs for a few hours, then the center bulb comes on , 20k 250w bulb, and they both run for two hours, then the right bulb comes on, 10k 250w bulb ... then left one goes off, center goes off, right goes off all a few hours apart ... with the depth and width of the tank, it gives a good illusion of times of the day even if the changes from one to the next arent as gradual as nature

 

[ddold]

the tank top ... all the plastic surfaces that are near the lights have been covered with the adhesive heat shield. The plastic hinge on the left warped before Id put the shield in there ... everything is now ok with the fans and heat shield in action. They hardly get warm to the touch.

 

[Dagwood]

How does it look lit up?

 

[Anonymous]

Nice job! But I think that plexi will warp over time. I'd switch it out for a piece of plywood.

B

 

[ddold]

I'll take an illuninated picture tonight ... didnt even think about it last night.

I thought plexi would warp, but was convinced to give it a try. It hasn't budged yet, but over time Im sure itll start to droop in the middle.