How high should I place my Metal Halides above water?

[nexus17]

Hi all,

As above.

Some background.

My Chiller has been working extremely hard since I changed my lighting from T5 to MH. Very Ex.

Was hoping to get some advises from the bros/sis here.

thanks in advance,

[Rupert]

I have my Dymax [2 x 150 watt] set sitting six inches off the water, and the MH's give off a lot of heat.

what temperature level are you trying to maintain?

[Goondoo]

at least 1 feet

[nexus17]

I set my temp between 26-26.8 deg now....used to be about 0.5 deg lower earlier....can't take the heat from the chiller as it kicks in every hr or so...... Makes my living room like oven

Now better, with lights on, should be about 2 hrs+, compared to about 3 hrs when I am using my T5, and maintaining about 0.5 deg higher now.

My lights are about 16 inch above water now....

[grey_fox]

Yeah, MH lights can generate heat and make your room feel like its an oven for sure.

I think what you need is ventilation actually. 16 inches above the surface of the water should be alright.

[nexus17]

The heat from the MH is manageable now after I changed the ballast from Mechanical to Electronic. However, the heat generated when the chiller kicked in is the killer..... That's why I am trying to place my MH as high as possible, without affecting the penetration depth of the lights. My tank is at 2 feet, some plants aren't doing well with T5 or PL....

Thanks for the advises so far.

cheers

[grey_fox]

2 footer with MH? I'm assuming you're using 1 x MH pendant?

[StanChung]

Erm, 2ft ht tank I think?
The disadvantage hanging the MH higher up is blinding glare.
The plants look straight up as well. Not very pleasing effect.
I off-set the MH lights to the front and tilt downwards a little.

I also plan to hang something down to block the glare...

[nexus17]

Hi Stan,

You are right, it's a 2 ft height tank. I am using 2x150W MH now for a 4x2x2 tank.

Tilting sounds good but would be tough to achieve if it is suspended from the ceiling...... keke

[StanChung]

Yup, that's what I face now. Either put extra thin cables to pull up the back portion or stick something heavy to front.