help on mh plcmt in canopy

[Marcel]

Hi,

The top of my canopy on my 80 gal. tank is 8.25 inches from the water surface. I have 2 175 watt 10000k mh bulbs with reflectors. I also have 2 110 vho actinics. The canopy is open on the back. The tank is 21 inches tall.

Any suggestions on mh bulb placement?
My main concerns are:
1. Not putting bulbs to close to water
2. Heat building up in canopy.

I could put a fan on the center top that sucks the air out of the hood, and one fan on both sides that blow in.
Should I have a box built that sits on top of the canopy (4"tall) to put the mh in or just put the bulbs in the canopy itself? What is the minimum distance you would put mh from water surface?

Thanks in advance for any suggestions.

[Elmo18]

Hi,

The top of my canopy on my 80 gal. tank is 8.25 inches from the water surface. I have 2 175 watt 10000k mh bulbs with reflectors. I also have 2 110 vho actinics. The canopy is open on the back. The tank is 21 inches tall.

Any suggestions on mh bulb placement?
My main concerns are:
1. Not putting bulbs to close to water
2. Heat building up in canopy.

I could put a fan on the center top that sucks the air out of the hood, and one fan on both sides that blow in.
Should I have a box built that sits on top of the canopy (4"tall) to put the mh in or just put the bulbs in the canopy itself? What is the minimum distance you would put mh from water surface?

Thanks in advance for any suggestions.

I have mine about 10 inches off the water surface, but they are 250 watters. I know people who have kept MH about 5 inches above water, but of course with shields and i believe had chillers. For me, I worry about heat and dont have a chiller, so I would go 10 inches or higher.

The fans should help. How many mh are you using?

- Elmo

[Marcel]

The fans should help. How many mh are you using?
- Elmo

I'm using 2X175 watt 10000 k mh. I will also have 3X110 vho actinics.
I was going to use 3X4 inch 30cfm fans from Hamilton. I have 80cfm fans from them but they make too much noise. They said the 30cfm ones are quiet. Also I'm using 2 16 inch polished reflectors for the bulbs, with 1 of the fans in between the bulbs on top sucking out the heat, and 1 on either end on the sides blowing in.

I do have a 1/4 hp chiller. I think though the bottom of the bulbs will be about 4 inches from the water, without shields. Of course the system is tied into a GFCI.

Should I maybe have a small box built on top so that I can increase the distance 3 inches or so?

[Elmo18]

Should I maybe have a small box built on top so that I can increase the distance 3 inches or so?

I would do that. 4 inches is just cutting it close for my taste Without shield....what if a fish jumps..and water splashes? These risks are far lessened if you increase the height.

8+ inches maybe? I have mine at 10" and am happy.

- Elmo