4x39w t5s on a100g long? - Lighting

mjcoussens · 07-23-2008, 02:38 PM

Does anyone know if the following setup would provide a sufficient spread of light over this tank? http://www.reefgeek.com/lighting/T5_...unlight_Supply

The tank itself measures 72"x18"x18" with a glass center brace. I'm not looking to keep anything extravagant plant wise just some vals, crypts, and java fern as this will be for discus. Adding CO2 is not a problem as I am planning on adding another regulator, etc off of the tank I currently have for my kegerator.

Thanks,

Matt

Brilliant · 07-23-2008, 03:22 PM

My 90g tank uses 2x54w with inferior reflector. I can grow Crypts, easy stems & swords. If I use 4x54w I can get robust growth, wider variety of plants and some nice colors.

mjcoussens · 07-23-2008, 04:35 PM

Good to know. I figured it would be enough light, and if not I suppose I could always just add another fixture.

Thanks,

Matt

hoppycalif · 07-23-2008, 06:37 PM

The problem is that the fixture is only 36 inches long and the tank is twice that long, so the ends of the tank will be very dimly lighted. Adding a second fixture would solve that, but leave you with too much light, unless you could leave some of the bulbs turned off. You could also raise the 36 inch fixture a foot or so above the tank, to get more even lighting along the length of the tank, but then the light intensity would be too low for almost all plants.

ingg · 07-24-2008, 05:18 AM

Quote:

Originally Posted by hoppycalif

The problem is that the fixture is only 36 inches long and the tank is twice that long, so the ends of the tank will be very dimly lighted. Adding a second fixture would solve that, but leave you with too much light, unless you could leave some of the bulbs turned off. You could also raise the 36 inch fixture a foot or so above the tank, to get more even lighting along the length of the tank, but then the light intensity would be too low for almost all plants.

But he pointed to retrofit kits... I'd assume put them end to end in a 6' housing?

Light level notes are dead on - I run 8x39 TEK over my 180g, and it runs pretty high light.

hoppycalif · 07-24-2008, 09:13 AM

Quote:

Originally Posted by ingg

But he pointed to retrofit kits... I'd assume put them end to end in a 6' housing?

Light level notes are dead on - I run 8x39 TEK over my 180g, and it runs pretty high light.

Now I'm not sure just what you get with that kit. The illustration shows only two bulbs and one ballast, but the description refers to 4 bulbs. If what you get is two of the kits shown in the illustration I agree that mounting them end to end would work fine.

EDIT: I also just noticed that this is a relatively shallow tank for a 100 gallon size. That will certainly raise the light level to the high category. A possible disadvantage is that with the kits mounted end to end, the light coverage may vary a lot from front to back in the tank. The tank is 18 inches front to back vs the narrow reflectors. You could "fix" this by spacing the two lights per kit several inches apart front to back.

mjcoussens · 07-24-2008, 12:48 PM

It's a stock photo that is the same on all the retro light kits. I was planning on arranging the lights in 2 rows of 2 lights, overlapped in the center a bit to compensate for the glass support beam. My only concern at this point will be dealing with the width of the tank and how well the lights will spread out. I'm guessing that viewing from the front will not be a problem, but that the individual lights will be quite noticeable from the sides. I realize that it's a relatively shallow tank for it's size, and that I could get away with regular of pc lights, but I've never really been a fan of them back in my reefkeeping days.

Matt