safe distance for lights

[thefatman]

can anyone give me a good measurement for a canopy?

what i mean is how high away from the water surface can my lights be?

i'll be running two 46.5" vho 110watt. over a 55gal. i'd like to be able to have them high enough that when i open the front door to reach into the tank, or feed, etc, that i wont burn my arm on the lights.

my initial plan is to make the canopy 12" high. 1 1/2" of that would cover the black border on the tank. leaving 9 1/2" for the space above the tank. figure roughly 3" for bulb space at the top, and that puts the bulbs about 7.5" above the water, and gives me a 7.5" door for getting my arm in there without removing the canopy.

will this work, or is it too high?

thanks!

[gumhead]

you cant burn your self on VHO's there just not that hot. I would make it so that your lights are as close to the water as possible. The further away the less light gets to your corals. 4 - 6 inches (closer is even better) is a good hight from water to bulb (for vhos) IMO

[Doug1]

Well they arent as hot as MH lights for sure but bumping into them can surprise one at times The canopy you are outling size wise would accomadate MH later tho it might get crowded

[bongobrian]

I agree with gumhead on this one--- you're gonna want the vho's closer than 12" off the water. I'd say 6" should be your max height of the water. If reaching into the tank poses a problem, you could always mount your front bulb a little higher than your back bulb. That way you're not sacrificing the par of your daylight bulb (assuming you put your actinic at the front). HTH

[thefatman]

well they wouldnt be 12" away, they'd be about 7.5" away.. but i see the point.

i suppose i could simply make the canopy 8" or 10" instead. and possibly have the whole top hinged, instead of just the front...

hmmm choices choices!

my other concern was moisture or splashes on the lamps, but i've resovled that. i'm going to install a sheet of 1/8" glass just below the lights that will protect them. though i'm sure i'll have some maintance monthly to slide the glass out and clean it/remove salt buildup etc...

[Doug1]

Jay my canopy os 6" and the bulbs are mounted on a lift up top. Wear shade when lifting canopy. FWIW, adding glass will add weight, it will catch a lot of salt creep and look unsitely, cause heat buildup leading to premature bulb failure , etc I find wiping the bulbs down every couple weeks is sufficient

[gumhead]

Im with Doug on this! I would not use glass! Believe it or not you will drastically reduce the light going to the tank, even if it is clean! (something to do with reflections and impurities in the glass) Never mind you will be cleaning the glass every night!!! It is easier just to wipe the bulbs every so often. I do it once a week. If you can make the canopy that can open up (the whole top tipping up) it will make it easier to clean the bulbs (which only takes a minute).

[big t]

I have a 55 w/ 4 110w vho's. They are about 4 or 5 inches off the water. I have it hinged so that the front 2 bulbs flip open over the back 2 bulbs. I cut the reflector in half, and I find that there is plenty of clearance to get my arm in there to clean the glass and what not. This was the best for me, but I never plan on adding MH lights to this tank. That is going to be on my next one

[Prismaco]

I have my lights about 3 inches above my tank...

-Paul

[NewReefer]

If you leave your top open do you use eggcrate? I had fish jump out at times. I use eggcrate across the top, but it does block light also. My hood is 10" high with 1.5" overlap. For me to add MH I need to raise the hood higher about 5 more inches. Ths way I can use MH and VHO's! I plan on adding a spacer to give me more height, but I'm not sure as how I can do this. I would like to leave the top open unobstructed but think the eggcrate is necessary. I also have glass in the center that i can't remove(support) but the water level keeps it clear. Also heat is increased when you lower lights to the water. I'm not sure what I can do when I add the MH lights, I'd hate to run a chiller. These are a few problems I'm having right now.

[NewReefer]

Hear is the tank as it is now.

[thefatman]

thanks everyone for the replies and advice. i jsut got home from picking up the lights and having the wood cut at lowes. (little hard to operate a saw with broken fingers )i decided to go with a 10" canopy, that will have a 1.5" overlap to cover the tank's trim. giving me actually an 8.5" inside height. the endcaps will place the bulb about 5 inches from the water, but i can also add spacers to lower the end caps if needed.

i did not buy glass, and i understand now why it would be a problem. the glass on my FW versahoods are bad enough!!! i don't know why i didn't think of it!

i REALLY do not want a canopy with a hinged top, for a few reasons. one being that i made my tank pretty high, and it's already hard enough to reach the bottom of the tank without a canopy, let alone, reaching from the top of one. the other reason being that i simply just dont like the look of a hinged top, versus doors on the front.

on the other hand, i always leave my self open to possibilities. the wood for this canopy was only 20 bucks cut and everything. so if after a month or two, i'm not happy, or see a problem, i can always build another one.

ok, i gotta go put this stuff together now!!! pics coming later.

thanks again - jay

[grazzit]

20? for all the wood cut to spec? You're joking me! I'm at a loss for words..... I'm GOING TO LOWES!

Oh and as for the lights having no shield at all, aren't you worried about splashes? or is that what the waterproof endcaps are for? I thought the endcaps were more for corrosion then actual waterproofing the bulbs.

[Hermit]

Jay, it may be a little late, but I but hinges on the top and the front. The front panel has hinged pins, this way I can pull the whole door off. Also, the hinged top makes it easier to pour water in if you don't have a sump.

[thefatman]

hey grazzit, yep 20 bucks.. .i used 5 1"x2" at .98cents each. 1 sheet of 1/4" luanne at 9.95 each. and 2 10' trim boards at 3 bucks each. so, i lied...21.00

and lowes cuts for free, so does home depot. they dont guarantee precision cuts, but the guy i dealt with hasa few fw tanks, and understood the neccessity for exact cuts, plus i think he was abit sympathetic of my broken fingers, which is why i had them do the cutting.

for each piece of wood you buy, you get your first 6 cuts free. so i was all set. and if you need more cuts, it's only 25 cents per cut!

naturally screws, nails, stain, polyeurathane, and a reflector would add some cost, but i already have all these items from building the stands. (i'm using aluminum foil for my refelctor :-)

hermit: thanks for the tip, if and when i redo this canopy i may try that out. i have a sump so water adding isn't a concern, however, it seems like a good idea for being able to get access to the lights for changing bulbs, cleaning, etc.. whereas the way i have it now, i'll need to remove the whole thing from the tank to get to the bulbs.. wish i would have read this first!!!! i'd need a heavy duty wood for the top though. dont think that luanne will be able to handle the stress of opening closeing etc.. let alone possible warping from moisture.

ahh well, it's only 20 bucks. quick and easy, and the lights are in place. now i have all my measurements i can take some time and build a better more functional top without a rush to get the lights over the tank.