# light for penetrating 4 feet of water?



## wizzin (Aug 14, 2007)

First post here but I've been lurking for a long time.

can't find anything on this anywhere I've looked. IF a person were to want to grow plants at a depth of 4 feet, what would be a good place to start looking for lights? I'm assuming MH, and a LOT of it at that? Should I think about targeting specific spots and filling in the "darker" areas with lower light plants? I'd like to fill in as much of the tank with natural plants as possible, and it's A LOT of square footage to cover. Any suggestions other than light are greatly appreciated.

This would be 1000 gallons. 10' long by 4' deep by 4' wide. South American in theme.


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## mrkookm (Oct 25, 2006)

Tom Barr used 4 x 1000watt MH as well as PC/FL on a 12ft 1600gal tank. You might be looking around the same ballpark for lighting.


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## wizzin (Aug 14, 2007)

Is this in the wrong place?

I'll sort of chime in on my own thread here. I was reading that volume doesn't necessarily equate to watts. Something I was not sure of. 1000 gallons doesn't necessarily mean 4000 watts are required. I always just heard the wpg rules and assumed they were pretty set in stone.

I read this: http://www.fitchfamily.com/lighting.html

based on their calculator, I come up with a need of 543watts for the 1000. More importantly, though, it made me think about surface area vs light. I'm going to start with (2) 500watt MH and see where it gets me. Probably algea hell more than likely.


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## mrkookm (Oct 25, 2006)

wizzin said:


> Is this in the wrong place?
> 
> I'll sort of chime in on my own thread here. I was reading that volume doesn't necessarily equate to watts. Something I was not sure of. 1000 gallons doesn't necessarily mean 4000 watts are required. I always just heard the wpg rules and assumed they were pretty set in stone.
> 
> ...


I agree some but you also do not have a standard sized tank. I'm thinking for you to get good spread you will have to raise the 500watters really high to cover your 4ft width with really good reflectors and in doing so you are going to loose intesity which equates to not enough light reaching the 4ft depth. This is reason _I believe _Tom Barr used the 1000watters; he could mount them high to cover the 4ft spread and they have the intesity to penetrate to the bottom. I'm no expert here so I could be way off with my reasoning but I'm sure you have an expert here who can chime in some more.


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## propor (Jul 24, 2005)

*wizzin *- I think all you need is to achieve 1/5 - 1/3 of maximum day light intensity (20000-33000lux) on the surface of water.
The surface of your tank is aproximately 4m2. If you use three metal halide every 400W(35000lumens) with light symiliar to day light, it will be good, especially if you want to imitate jungle enviroment.
All flux must go to the tank, and any point on surface must be lighting. You should to choose quality reflectors with something about 90" angles of light distribution.

Sorry about my english.


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## hoppycalif (Apr 7, 2005)

Just a comment on why so few responses to this - yes it is in the right forum, but very few of us have faced a problem similar to yours. Four feet is about twice the depth we are used to dealing with, and 4 feet is about 2-3 times the width of the top that we are used to dealing with. Some of us can do a good guess about what you need, but experience will be lacking. I can say that when the tank is that big, you surely don't need 4 watts per gallon for a planted tank. But, once you start raising the lights high above the water, you lose so much light intensity, unless you have very, very good reflectors, that who knows what wattage you need.


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## rs79 (Dec 7, 2004)

GE makes a nice carbon-arc bulb; it's 10,000 watts. It only comes in one color and is used in lighthouses. I'd use that. Otherwise you're gonna need a lot of sunlight as well. Look a the 50,000 litre tank in the Dupla book, there's like, 7 skylights there as well as a bunch of metal halides.


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## shake (Feb 26, 2006)

rs79 said:


> GE makes a nice carbon-arc bulb; it's 10,000 watts. It only comes in one color and is used in lighthouses. I'd use that. Otherwise you're gonna need a lot of sunlight as well. Look a the 50,000 litre tank in the Dupla book, there's like, 7 skylights there as well as a bunch of metal halides.


WOW, 10,000 watts. I didn't even know globes came in wattages that high.

The Dupla tank has 2 skylights and is 10,000 ltrs. 

I think Amano's home tank also has skylights.

Skylights could be an option to providing some of the lights. I have seen some reef tanks that have skylights supplementing the MH and they look great.


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## ruki (Jul 4, 2006)

I agree with those who suggested using metal halide lamp. They are closer to a point source, so the reflector can be really good -- it sends a rather narrow beam into the tank at a near perpendicular angle so light doesn't get absorbed bouncing around the tank as much as other light sources.


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## gf225 (Mar 26, 2005)

Amano's has 16x 150w MH and skylight. 4 x 1.5 x 1.5m tank I think.


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## Newt (Apr 1, 2004)

This might work:
http://www.giesemann.de/76,2,,.html


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## BryceM (Nov 6, 2005)

Your question isn't easy to answer, partly for lack of comparable projects, and partly because you haven't really stated your goals. With a 4 foot depth it must be assumed that you will NOT be using stem plants or any high-demand foreground plants (like glosso or HC). Even if you wanted to, there would be no practical way of maintaining such an aquarium. Mine is 2' deep and planting HC at the front of the tank involves a stepladder, 18" tweezers, and removal of a fair amount of clothing. Placing stem plants in the back corners of the tank is possible, but just barely. The bottom of the tank isn't that high either, just over 3' from the floor - about right for viewing IMO.

The only practical plants for a 4' deep tank would be rosette plants (Echinodorus, Crinum sp, Aponogetons, Cyperus, Vals, Nymphaea), crypts, ferns, aubias, and maybe slow-growing stemmies like Blyxa. None (not a single one) of those plants require high light.

Taking that into consideration, the task of lighting a 4' deep aquarium isn't that difficult at all. With good reflectors a single 250W MH for each 2'x2' of surface area would certainly be just fine. You could add more, but why bother.

You'll be able to grow certain species that you just don't see very often in planted tanks. The larger Echinodorus, crypts, and vals will give you endless possibilities that will be stunning. Use regular crypt and anubias species for the foreground and midground and you'll be all set. Add a little clump or two of stemmies if you must, but keep them localized and in a place that is easy to get to.


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## Edward (May 25, 2004)

3 x 400 Watt 10K for 8 hours a day


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## defdac (May 10, 2004)

It's true an unreflected bulb looses alot of intensity when moving away from the object to be lit, but we're talking almost perfectly reflected light here.

The attenuation of light intensity in air will be unnoticable.

Let's say you have 14700 lux (276 mmol/m2 PAR and 165 mmol/m2 PUR) as in the case of Amanos 4x1.5x1.5 metre tank at the bottom. It will be about 20000 at the surface (370 mmol/m2 PAR and 223 mmol/m2 PUR).

Both those values are much greater than any average tank. The reason Amano doesn't have glosso or HC is not because of having to little light - my guess it has to do with the problems he will have pruning it. He even let a lot of plants go emersed shading the whole monster... 

Wizzin, 2x500 well reflected watt will be enough to do HC in your 3x1.2x1.2 tank if you manage to spread out the light evenly. It will give you around 11000 lux at the bottom and 200 mmol/m2 PAR and 120 mmol/m2 PUR which is enough for HC.


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