I'm sorry, I need some light advice

[Dazureus]

Hi. I've been running my 50 gallon breeder (36x18x18) for three years now under (3) 95 W VHO's. I have some soft, LPS, and one Acro and everything is doing okay. I would like more confidence with SPS's and would like to switch to Metal Halides. Having read through 16 pages of the search function here and have developed a few questions.

1. If the recommendation is to have one MH bulb per two square feet, what do people with 40 breeders, 50 and 65 gallons do (36" tanks)? One bulb or two?

2. I've read Sanjay Joshi's tests on reflectors and recognize the amount of light decay at 18" horizontal from the bulb. I was hoping to go with (1) 400 W MH for future upgradability. My first step will be a 65 gallon (36x18x24) then down the road maybe a 220 or something. I would like a light I can use on all three tanks (of course more will be neede on the 220). Any thoughts about a 400 W on my current setup?

Thanks for all replies.

 

[ChrisRD]

Do you have a centerbrace on this tank?

 

[Anonymous]

You can also find very good lighting information (much written by Anthony Calfo) on http://www.wetwebmedia.com
Follow the marine links, then set or inverts, lots is cross referenced.








two.

 

[LA-Lawman]

Good thinkin' wolfman.....

in a Breeder I would be worried by heat unless you elvate that 400w'er a bit.

In a 40g i had - 36 x15x15 (i think those are the measurements)

1 175w 10k halide and 2 55w PC's . I had them 7" from the surface in a fan cooled canopy.

 

[Dazureus]

Thanks for the quick replies.

There is no center brace. I bought the tank used and the previous owner removed the center brace.

Thanks for the link. I'll start digesting the information.

When You say raise the 400 W up a bit, is that more than the standard 8-10 inches? I'm sure I'll have to fan cool the canopy and raise the lights at least 8 inches, but I might be deterred if I thought I would need a chiller. Real estate is at a minimum right now so the tank must be self contained in the stand.

 

[ChrisRD]

There is no center brace.

In that case, you can get away with one lamp. You can keep the most light demanding stuff in the center of the tank and work out toward either side from there with the less demanding stuff.

If you're primarily concerned with SPS I think you'll see the best colors with a 250 DE or a 400 Mogul. This would also be a more appropriate lamp for your future setup.

IMO cooling will be your biggest hurdle. Having one lamp will make it easier to keep temps under control for two reasons. First, you'll only have half the heat to start with (one lamp instead of two), and second, with a single lamp you'll have the fixture mounted higher to get even light spread, so less heat will be radiating into your tank.

Can you run open-top or modify your canopy? I think you'll have to be about 10-12" over the water with the lamp to get good light spread and control heat.

JMO

 

[Dazureus]

Right now I don't have anything in between the water and VHO's but I'll make a new canopy to accomodate the MH fixture. Are there wider reflectors that would help distribute the light across the tank?
For the canopy, I was planning on creating a open back with top ventilation and fans to help with the cooling. The tank is in the living room with an AC unit not too far away. A 10"-12" distance is not a problem. Thanks for the suggestions. You've all been a great help.

 

[ChrisRD]

Are there wider reflectors that would help distribute the light across the tank?

I use DE halides, not Moguls, so maybe someone else can offer some advice there. Also, check out this month's edition of AA for some comparisons of Mogul reflectors:
http://www.advancedaquarist.com/issues/mar2003/feature.htm

For halide lighting that's going to be mounted inside a canopy, Sunlight Supply has nice stuff, both Mogul and DE units. Coral Reef Aquarium is a sponsor of the board, and they carry SS stuff.

For the canopy, I was planning on creating a open back with top ventilation and fans to help with the cooling. The tank is in the living room with an AC unit not too far away. A 10"-12" distance is not a problem.

With this setup IMO you'll be able to control tank temps just fine.

 

[Anonymous]

Get a single fixture from either Giesemann or AquaMedic. I run both of these on different tanks, and I cant tell you how happy I am with them. The 1 bulb per 2' rule is bunk if you ask me. I have a single Giesemann fixture (250W) over a 4' corner tank, and it lights the whole width of the tank.
Cheers
Jim

 

[ChrisRD]

Get a single fixture from either Giesemann or AquaMedic

Just to clarify...

If you're going to run an open-top, I like the Giesemann (I have two) or AquaMedic pendents too. The SS units would be fine as well, but I think the German units look a bit nicer.

My experience with the Giesemanns is, just as Jim said, that they have excellent spread.

If you're going to build a canopy (which is what I took from your posts) I think the SS stuff would be worth looking into (especially if you're looking at using a Mogul lamp).

HTH