Reflector.

[fishboy]

Hi all,

Anyone have experiance with DIY reflectors?

I just ordered up the parts to add metal halide to my tank(currently 2 55W PC's and 2 30W NO actinics). I went with a Iwasaki 250W 6500K bulb and mercury vapor ballast. I'll keep my 2 actinics with it.

My tank is 36" long and I'm woundering if it would be better to use a small reflector on the MH between the actinics(currently mounted on a flat white plate) or a reflector that runs the full length of the tank with the actinics mounted on the sides.

A rough side view of full length version might be:
_ _
/ \ / \
_/ 0 \_
/0 0\

Or with a reflector only over the length of the MH:
____________
0 /0\ 0

Anyone have any brite ideas? images/smiles/icon_biggrin.gif

[fishboy]

Sorry. My stick drawings got messed up.

Full length version:

http://www.dataonly.net/images/MH.jpg

Only over MH bulb version:

http://www.dataonly.net/images/MH2.jpg

[Silverfish]

Hi Dwayne,

I have the same size tank..36L x 18W x 21T and I ran my 250W MH perpendicular to the tank. I made my own reflector with white aluminum sheet metal and bent it up similar to the store bought reflectors. (I am going to make one out of polished-hammered aluminum when I find it)

Right now I have two 3' NO actinics at the front of the tank. In the near future I am going to add a third actinic and make them all VHO or overdriven.

My MH reflector is 13" long and both actinics fit in the front fine (even tho my hood is angled at the front 6 inches)

The third actinic will have to be screwed to the back of the hood on the vertical, just below the MH socket.

Apparently, it is better to run your MH lamps perpendicular to your tank if you can...so I heard.

I wish I had a camera or could draw you a pic of my setup.. images/smiles/icon_wink.gif

HTH

[pocilipora]

Personaly I would go with your last choice as it seems to work well for me

[fishboy]

Bruce,

Does your tank have a center brace? Mine does and it cast a bit of a shodow. Also I'm a bit worried about the heat of the MH if I mount it over top of it. I was thinking of cutting it off images/smiles/icon_confused.gif . The tank is a 54 gallon Hagen and the bigger Hagen tanks I've seen(a bit longer) don't have the center brace and the plastic cap appears to be the same as mine(thickness, highth etc.).

Any thoughts on how large a fan I should put with the 250W MH? I was thinking around 60 CFM?

[pocilipora]

You may want to go with a pendant style of lighting, as for cutting the center brace that is probably not a good idea. The tank was built that way for structural reasons. But a way of getting around that would be to silicon 2 strips of glass fron and back to the inside of the tank. Then you could cut that brace out.

[Silverfish]

Hey...
I have no brace on my tank...

as for cutting yours out, I would not recomend it, onless you go for Pocilipora suggested. Could be tricky with a tank full of water. images/smiles/icon_eek.gif

Maybe got for two MH if you have the $ ...one on each end images/smiles/icon_biggrin.gif

some people my put their MH over the glass brace, but I wouldn't.

[Silverfish]

oh ya.. fans images/smiles/icon_wink.gif

I am running two 105 cfm fans blowing into my hood, both fans on a speed controller running about half speed. Seems to work fine... no temp swings... bit o evap tho images/smiles/icon_wink.gif