# What wattage and lumen to use?



## Synthtcd (Feb 15, 2007)

Can anyone tell me how much wattage I will need to grow healthy plants in a 24"Tall 18"wide and 18" deep exo terra? It will be heavily planted in the bg and on the bottom, but plants will be up to the very top of the tank. I've already purchased the plants, I have many orchids, nepenthes, ferns, and a multitude of tropicals. I'm looking for 18" flourescents, but I have no idea what wattage and lumen to get. I know I'm looking for around 3000-5000k? Any advice is greatly appreciated, Brooke


----------



## wildboxer (Oct 22, 2006)

I'm no lighting expert, so hopefully some of the more technical people will respond. I'm running 48 watts of HO T5's on my 24" tall Exo Terra. My broms are coloring up very nicely. But, I don't think they make an 18" fixture. 

I see that Exo Terra is going to be selling a fixture for the Exo Terra enclosures.


----------



## allanschon (Mar 25, 2007)

I've been growing orchids under lights for a little while, and it really depends on placement and the variety. It's pretty hard to give most orchids too much light under 18" flourescents, especially with plants above providing partial shade. If you could post a little more information about the species you've bought, it would certainly help.

Generally, though, I'd get the highest light output you can find and order your plants from the top down, higher light requirement to lower.


----------



## Synthtcd (Feb 15, 2007)

Here is a rough list of my plants, some are proper names, some are layman's terms:

Drosera Adelae
Goodyera Schlectendaliana
Tillandsia Velutina
N. Muluensis x Lowii
N. Gymnaphora
N. Ramispina
2 x Masdevellia
Pothos Satin
Oncidium "Little Twinkle"
Rex Begonia
3 x Maidenhair Ferns
2 x Tropical Ferns
Calathea
2 x Syngonium
Creeping fig
Fittonia
Aglonema
Spathiphyllum
2 x Baby's Tears
Goldfish Plant
Staghorn Fern


----------



## allanschon (Mar 25, 2007)

Well, I haven't done much research on lighting in the 18" range, but based on the plants you've listed, I'll go with my initial recommendation. 24" down is a long way, and even though many of the plants you have are lower light plants, you'll probably need as much as you can get to the bottom.

I'm building a viv with the 24x18x24 exo-terra, and I'll probably be going with two 55W compact flourescent tubes, each providing about 4100 lumens. You might consider using the 36W versions; they give about 2500 lumens, and should last quite a while.


----------



## defaced (May 23, 2005)

I'm running two 65w FCs and Zach (ZBrinks) is running one 85w CF on that size tank. These are both Lights of America fixtures we picked up at Home Depot. You'll have to get the lights up off the top of the tank because of heat, but aside from that they're great.


----------



## zBrinks (Jul 16, 2006)

My broms in the upper 12 inches are coloring up nicely, and I have some more light-demanding orchids that bloom for me airly regularily. I get a nice temp gradient, from about 82 at the top to 74 or so at the bottom.


----------



## Studdlygoof (Feb 10, 2007)

I know with aquatic planted tanks you generally go with a 2 watts per gallon rule...i was talking with the guy from AHSupply on Friday and he said that lights along the 67000 K range are the most natural looking light...not to plug for the company but he was very helpful to me, espicially being someone who lacks knowledge in the light and electrical department....


----------



## Synthtcd (Feb 15, 2007)

> I'm running two 65w FCs and Zach (ZBrinks) is running one 85w CF on that size tank. These are both Lights of America fixtures we picked up at Home Depot.


So how long are these bulbs? Probably 24"? I only have a Lowe's in my area and their selection was extremely poor. I could only find 35w flourescents in an 18" size. And the old man from lighting wouldn't stop following me and insisting that I buy these ineffectual under the counter lights, seeing as that was the only 18" fixture that they offered. :?


----------



## zBrinks (Jul 16, 2006)

The 85w fixture itself is around 16'' long, and the 65w fixture is even smaller. You could fit either over an 18'' tank, as the exo-terras I have running are 18x18x24.


----------



## Synthtcd (Feb 15, 2007)

That does sound perfect, where did you find the fixture? Also at Home Depot? Is it the sort that's meant to be bolted to the ceiling? Do you know off hand how much the fixture/bulbs cost you?


----------



## Studdlygoof (Feb 10, 2007)

Does Home Depot carry Compact Floresent (CF) fitures? I've only seen them cary regular Floresent fixtures that take the T5 - T8 bulbs....i'm going to have to check into that


----------



## Synthtcd (Feb 15, 2007)

When I look on ebay for compact fluorescents I see several people going on about CF having more wattage than incandescent. For example one auction claims:

"They are 23 watts but are equivalent to 120 watts of incandescent light wattage."

"This unit's bulbs are rated to makes 3600 real lumens, about as much light as a "65 watt (=500 watt, 8000 phony lumen) fluorex" 

Should I give any attention to these claims or are they just ranting about their product?


----------



## salvoz (May 10, 2004)

I would typically disregard the "equivalent to" language regarding the wattage comparisons, although incandescent lights are indeed very inefficient in their light output and generate tons of unwated heat. For a general artificial lighting rule a thumb in the hydroponic growing world, you can grow most plants/veggies by using a minimum of 40 watts of HID or flourescent lighting per square foot. But this is probably overkill for most vivs...unless they are very tall or the plants are light-needy. Maybe shoot for 30 watts per square foot of viv floorspace and watch the plants for signs of either too much or too little light and adjust accordingly...just watch your temps!


----------



## defaced (May 23, 2005)

These are sold in the area for outdoor lighting. They are intended to be bolted to a conduit box, but you don't have to. DartMan made a thread a few weeks ago on how people mounted theirs. 

The 65w fixtures are 40 dollars each and replacement bulbs are between 10 and 15 bucks. When you buy the fixture you get a bulb and all of the wiring hardware. The only thing you have to do is wire it to either a box or a cord.


----------



## Studdlygoof (Feb 10, 2007)

salvoz said:
 

> ...you can grow most plants/veggies by using a minimum of 40 watts of HID or flourescent lighting per square foot...
> 
> ...shoot for 30 watts per square foot of viv floorspace...



Salvoz - I think you have some useful information but i'm a little confused on your formulas...

Your first statement makes it sound like we should do calculation by square feet of the ENTIRE tank (as in the total volume)

The second statment makes it sound like we should calculate wattage according to the square foot of viv floorspace (...which would be area...)

Defaced - Thanks for that info....never thought to check in outdoor lighting...now are the CF bulbs used for those the straight tubes or the spiral syle?...I have heard that with the spiral style you actual loose more lighting because of the design of the bulb (designed to spread light in every direction instead of a focused area as with straight tube CF)


----------



## salvoz (May 10, 2004)

Sorry if there was any confusion. But volume is measured in _cubic _feet, not square feet, technically. For example, when someone says they have a 600 square foot apartment, it is understood that they are _not _referring to the volume of that appartment, merely the length and width of its floorspace, i.e., its area. Either way, I was definitely referring to floor space, measured by length and width. I would offer no guidelines as to watts per cubic foot of vivarium--that would really be treacherous!


----------



## defaced (May 23, 2005)

These are shaped like a spiral CF, but each tube is straight. You'll understand when you see them. 

Power/area is a poor way to characterize light being put into viv. Power consumed doesn't factor in the efficiency of the bulb which varies greatly for each kind of bulb. Area doesn't take into account the distance the bulb is from the floor of the tank - this is different than volume because we are interested in light flux which is a surface characteristic. For example, I may have a 3000 lumens over 1 sqft at the source, but as I move from the source, say 1ft, I'll only have 1500 lumens/sqft, then at 2ft I only have 750 lumens/sqft. Because of this fall off rate light is not an easy thing to create an accurate rule of thumb for.


----------



## salvoz (May 10, 2004)

Agreed that watts per square foot is a poor measure, its just a point of reference. i never said it was accurate! Of course, considering all the variables involved, and we can go on all day about those, no rule of thumb here can be accurate. That said, if you are using a tank less than two feet tall, and don't have a light meter, and don't know the lumens required by each of your plants, and all the other factors involved, its as good a starting point as any...


----------



## Studdlygoof (Feb 10, 2007)

Good stuff guys...no worries...i won't hold anyone to their formulas...just trying to build an understanding of the entire concept...i do agree that i need to invest in a good light meter because that would be the definate way to tell if i have enough light or not...mucho gracias


----------



## Synthtcd (Feb 15, 2007)

Okay, I finally got my light! This thread helped tremendously in choosing a critical part in this viv's setup. I'm so grateful for the advice, particularly, it seems Defaced is really guiding my way here. I'm now getting a Mini-Jet 606 powerhead, will be wiring up fans according to his article, and found this great light too. 

So I ended up getting the 65W spotlight, it was $44 which is much more than I would liked to have paid. I am only a biology student afterall, and not currently on a paid stipend, there goes this weeks dinner! I hope 65W will suffice, I saw halogen lights that were 125W for the same price, but I'm guessing its doesn't promote plant growth. Now the real fun is figuring out how to mount it!


----------

