Bulb Placement in Hood, How close is too close?

12 Inches is the standard from the bulb to the water, I would suggest at
least 6 inches between bulbs. Why not upgrade to 400 MH ???
Run 20K bulb and you get better color, You can run a Digital MH ballast and
cut your cost too, cheaper in the long run - they save you on hydro plus
they let your bulb last longer


"Dave Keyes" wrote in message
nk.net...
Hello group,

I have been considering adding some more light to my existing hood over my
75.

I currently have ( 2 ) 175 w 10K MH and ( 2 ) 65w Actinic bulbs.

I would like to add some more PC lights and have the room to physically put
them in there but they will be close to the MH bulbs.

How close is TOO close?

TIA

Dave K

Dave

If you are thinking about going MH do not us the acrylic below the MH for
whatever reason. You will melt it within about 3-4 hours of the bulb in
operation. MH bulbs are extreme in heat. I would suggest either getting rid
of the cover or replacing it with glass.

As per the cost of a ballast

Let me enlighten you on a new product

Reef Tech Digital MH Ballast

Cost effective in every way. So far this ballast can drop you 20 - 60% in
you daily hydro cost, so you can run more an higher watts and still get what
you want out of the bulb

Here listed are the benefits
Compact & Light Weight (Small Case .65 kg. 1.41 lb., Large Case 1.2
kg. 2.7 lb).
-Easy to install

-Less expensive mounting details

-Reduces housing, structure and pole costs.



Approved to CSA and UL standards


-Can be installed in most jurisdictions



Microprocessor Control


-Provides all protective functions

Microprocessor controlled Active Power Factor Correction
-Brown out protection

-Can't over drive the lamp

-Longer lamp life

-Consistent lumen output over lamp life

-Consistent color rendering

-Provides "soft" lamp start up, minimizes in rush current

-Low Total Harmonic Distortion



High Frequency or Very Low Frequency


-No flicker

-Higher lamp efficacy

-Cooler lamp and ballast operation

-Softer lamp start up

-Longer lamp life



Exceptionally low ballast loss ( 5-10W )


-Increases energy savings



Crest Factor 1.41


-Protects the lamp



Broad Operating Temperature Range -25C to +75C Case T (-13F to +167F)

-Can be used in most outdoor or indoor locations



Progressive firing

-Fires all manufacturers bulbs

"No Lamp" feature
-Prevents "end of life" syndrome which can damage the fixture




"Dave Keyes" wrote in message
news I certainly have though of upgrading to either 250w or 400w Metal Halide.

I would lean more towards the 400w just because the jump to 250w from 175w
doesn't seem to justify the cost of new ballasts.

The problem with going to 400w is that I currently run my bulbs in a metal
( name brand ) housing that sits directly on top of the tank with a piece
of acrylic beteen the bulbs and the water.
This locates my bulbs less than 6 inches above the surface.

I do not have a standard metal halide canopy that puts the bulbs much higher
over the water surface.

I am afraid that 400w MH would cook something. ( water , acrylic, my
existing pc lamps ).

You got my mind gong though.

Why not, replace everything ( my current MH and PC combo ) with ( 2 )
400w MH ?


Hmmm.....

Thank you for the input.

Dave K

"David J. Nicholson" wrote in message
able.rogers.com...
12 Inches is the standard from the bulb to the water, I would suggest at
least 6 inches between bulbs. Why not upgrade to 400 MH ???
Run 20K bulb and you get better color, You can run a Digital MH ballast
and
cut your cost too, cheaper in the long run - they save you on hydro plus
they let your bulb last longer


"Dave Keyes" wrote in message
nk.net...
Hello group,

I have been considering adding some more light to my existing hood over my
75.

I currently have ( 2 ) 175 w 10K MH and ( 2 ) 65w Actinic bulbs.

I would like to add some more PC lights and have the room to physically
put
them in there but they will be close to the MH bulbs.

How close is TOO close?

TIA

Dave K

Just to let you know I am not shooting through my hat

Here is the comparison test


150w Magnetic Ballast
150w Electronic Ballast
175w Magnetic Ballast
175w Electronic Ballast
250w Magnetic Ballast
250w Electronic Ballast

400w Magnetic Ballast
400w Electronic Ballast

Operating Temp [F]
155
99
140
102
170
122
185
127

Power Factor
.66
.99
.65
.99
.62
.99
.67
.99

Input voltage
120V
120V
120V
120V
120V
120V
120V
120V

Input Current
1.9 amps
1.25 amps
1.8 amps
1.47 amps
2.5 amps
2.10 amps
4.0 amps
3.37 amps

THD
32%
6%
31%
6%
33%
6%
33%
6%

Current Crest Factor
1.7
1.41
1.7
1.5
1.8
1.5
1.7
1.5

Physical Size

2.5" h x 4.75" w x 6.5" L

2.5" h x 4.75" w x 6.5" L

2.5" h x 4.75" w x 6.5" L

5.5" h x 5.0" w x 7.25" L




· Available 70, 150, 175, 250, 400, 600, & 1000 watt (600 & 1000watt -240v
only)

· Will fire any mogul base lamp on the market including 12,000K Sunburst
and HQI

lamps.

· 250-1000 watt units available with dimmable control

· All units available with ambient light on/off control

· Water resistant, epoxy filled, extruded aluminum case

· Multiple power management control chips protect these ballasts.

I do not have a standard metal halide canopy that puts the bulbs much higher
over the water surface.
I am afraid that 400w MH would cook something. ( water , acrylic, my
existing pc lamps ).


2" from the water with 400w MH bulbs wont be a problem.

go for it

however you can place PC lights within about 8" of a 175MH bulb.

--
Richard Reynolds

OK guys,

I think some things got missed here.

I DO have metal halide ( 175 ) next to that acrylic and it is not melting
it.
It has been that way for a year.

What I wanted to do was add more bulbs ( PC ) in the hood.
The PC's that are in there now are about 4" away from the MH.

What I was wondering is that if I add more PC, How far must they be from
the MH bulbs.

Thanks


Dave K



"Rbuehler9" wrote in message
...
2" from the water with 400w MH bulbs wont be a problem.

go for it


I run most of my 400s about 4" above the water surface. Single end/mogul
base.
No glass.