Heat management for Metal Halide lighting

[Aquaculture]

I'm toying with the idea of getting a MH light. The ripple effect I saw at Qian Hu was simply too cool to foget...

Its for a 422 tank and I do not own a chiller. I'm thinking that if I hang it high enough about 35 - 45cm, will I be wrong to say the water won't get so heated up? Or if I've a fan blowing the heat away...

If the 1st theory stands, how power should the MH lamps be and how many should be used?

Thanks for your input.

[BFG]

No experience using a MH lights but here's what I know about them.

You'd probably need 2x 150w mh. Basically, a single 150w mh pendant/lightset will typically light up a 2-2 1/2 ft area. There are a few types of mh bulb available, Single Ended ( SE ) and Double Ended ( DE ). Single Ended mh bulb are bulbs that are connected to the bulb holder at one end of the bulb whereby Double Ended mh buld have both end of the bulb connected to the bulb holder.

As for reflector, there are also a few types available. The Parabolic , the Spider reflector and the Diamond reflector. The Parabolic reflector comes in a housing and can be hung as it is. The Spider and Diamond reflector comes 'bare' and you might need to conceal it if you don't like the 'bare' look. From what I've read in the internet, the Diamond has the best reflecting ability. There's a newer version of the Diamond reflector but it's a rounded version. These are available in diy version, meaning you need to have a fixture to hold these reflector.

Then, there's those that are commercially made for aquarium setup. Brands like Geisemann, Solite, Dymax and such that are specifically built for a specific size of tank. They do not need to be meddle with except that they need to be mounted or hang during installation. These are complete system unlike the ones mentioned above which need to be adjusted and mounted by the owner themselves, kind of like a diy kit.

So in the end, you need to look into which setup is suitable for your tank. You might go with the diy bare reflector look or a commercial setup. Both has it's pro and con.

[tawauboy]

mh, like most other types of llight, emits infra red. so you cannot blow the heat away using a fan.
however, a fan/fans will help to cool the tank by evaporative cooling.

[o2bubble]

i think a chiller is a must for using 2x150w MH. the heat is really too much to lower by just fans. Even if you can put many fans, you need to top up water everyday.

[Aquaculture]

Thanks for the advises guys... seems like a chiller is a must to complement MH lamps.

[ssathesh]

for a 422 u need at most a single 250v MH. dont overkill. i used 1x250v for my 522. no problems at all.

but choice of bulb is important. only bulb worth is the BLV series 20k.

and chillers are a must, even with FL tubes! why?

we live in asia, all we get is sun or rain. its good when it rains but what happens when we get a dry spell? its a one time investment, with proper maintainence will serve u a long time.

[Shadow]

1x250v for 522? does the light enough to cover the entire length of your tank? I got one 150W for 3ft tank and it is just enough, expecting the plant at the left and right to grow slower.

[ssathesh]

i used a 20k bulb for 8 hrs a day. hanged it 1.5 feet away. had no problems...

[Aquaculture]

i used a 20k bulb for 8 hrs a day. hanged it 1.5 feet away. had no problems...

This '1.5ft above, had no problems' is petaining to shadow's question on light coverage or in terms of keeping the water cool?

[ssathesh]

This '1.5ft above, had no problems' is petaining to shadow's question on light coverage or in terms of keeping the water cool?

its light coverage.

[tcy81]

I'm toying with the idea of getting a MH light. The ripple effect I saw at Qian Hu was simply too cool to foget...

Its for a 422 tank and I do not own a chiller. I'm thinking that if I hang it high enough about 35 - 45cm, will I be wrong to say the water won't get so heated up? Or if I've a fan blowing the heat away...

If the 1st theory stands, how power should the MH lamps be and how many should be used?

Thanks for your input.

For 4x2x2ft i think you need 2x150w MH, if possible get those with 2 more
T5HO 54w tubes.
you need a chiller to cool the water down