MH and Central Brace

[ldmk]

I am working on putting together a 190 gallon acrylic tank (72" X 24" X 25"). Unfortunately, because I wasn't aware of this problem at the time I purchased the tank, the tank has a foot-wide, acrylic central brace. At the same time, because it is a 72" tank I initially wanted to put three 250 watt MH lights in the canopy.

I realize that putting a MH over an acrylic central brace is a big "No No," however, the one difference between my situation and most of the other posts I've read on TRF is that I built my own canopy and so my canopy is 18" tall. Hence, any MH I put over the central brace would be approximately 15"-16" above the central brace. This raises a couple of questions:

1. Is it safe to put a 250 watt MH bulb over an acrylic central brace when the bulb will be about 15"-16" above the brace?

2. If not (i.e., if I am stuck with only two MH bulbs), should I put in two 400 watt MH bulbs over the two openings? And should I aling them parallel to the front of the canopy (instead of perpendicular - as recommended)?

3. Also, I was planning on putting in two 60" Actinic "03" VHOs along with my MH. If I am knocked down to two 400 watt MH would it make sense to put in two 60" Daylight VHOs in addition to the two 60" Actinic VHOs?

Thanks in advance for your responses. [For the sake of argument let's assume that I want to be able to keep everything from LPS to clams. Real reason is that I think I have a one time shot at investing in the high cost equipment before SWMBO clamps down on the funding ]

K.M.

[1coolvw]

i too have a similar setup, it is a bit of a scare tactic saying no no on halide over the brace. My hood (hamilton fixture) has a spash guard (1/4" acrylic) below the halides, this drastically reduces the heat on the brace. the brace is easy to touch, probably about 100°F, so very little issue.

With your height, i'd say, no issue.

[Geoff]

i have the same issue, but instead of an acrylic brace mine is plastic. i went with 2 400w over the rest of the tank. i think it works out fine. i think it is more of an issue of having a shadow in the middle of the tank, and not necessarily melting.

G~

[ldmk]

Geoff:

What other lighting are you using in addition to the 2 400w? Also, are your 400w lights radiums? Is there an advantage to using radiums over regular MHs?

Apologies for the raft of questions.

K.M.

[Geoff]

no apologies necessary, questions are fine and good.

i also have 2 165w VHO actinics along with the MH. the Mh are 400w iwasaki 6500K bulbs. bulb choice is tough one. i went with the iwasaki's because i like the truer colour and the higher total output. if you go up to the radiums then you prolly do not need the actinic supplimentation, but the total output is not as great as the lower K bulbs. a lot of the 10K are a good compromise between the two.

HTH,

G~

[ldmk]

Geoff:

Thanks for the information. The 6500 K bulbs and 2 VHO actinics is what I am leaning towards. Although I might go with the 10000K for a little more bluer tones to the tank.

K.M.

[FISH]

Hi KM,
I have a 120 aga and run 3 400 watt MH. One Iwasaki 65k over the plastic center brace and 20k HQI radiums on the sides.
What I have done is run the return from one of my fuges on to the center brace . This keeps it cool. I do get a few bubbles in the tank but I don't mind a natural look.
I hang em about 8 inches above the water.

[ldmk]

Fish:

That's a really innovative idea. I'll keep that in mind as an option as I try to figure out the lights and plumbing.

K.M.

[FISH]

And it also makes a good breeding ground for snails