SolaTubes for reef tanks
- Thread starter JohnL
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Electrobes
Montipora type guy
Here's a question for you sun tubes guys/gals:
What's the largest light foot print a 21'' sun tube can make given the corals (Soft only) are under maximum of 6 inches of water?
I've been planning a coral farm for some time and had originally gone with halides but am convinced that the sun tubes/skylights is best.
I prefer sun tubes versus squared skylights but obviously want to go with what works. The reason I ask about the foot print is because at current I am planning on using 300G tubs which are about 6' X 5' rounded. I am still looking into other holding tanks but for now would like to consider my options assuming I will be using the tubs.
Your thoughts?
What's the largest light foot print a 21'' sun tube can make given the corals (Soft only) are under maximum of 6 inches of water?
I've been planning a coral farm for some time and had originally gone with halides but am convinced that the sun tubes/skylights is best.
I prefer sun tubes versus squared skylights but obviously want to go with what works. The reason I ask about the foot print is because at current I am planning on using 300G tubs which are about 6' X 5' rounded. I am still looking into other holding tanks but for now would like to consider my options assuming I will be using the tubs.
Your thoughts?
mborn
New member
I’d say ~ 36†of bright light and possibly up to ~ 48†(which would be pushing it IMO) of a less intense light with the tube higher above the tank. If you’re going to go with the tube higher off the water to get a larger coverage, I’d look into making a bell reflector for the end of the tube (like hobogato made for his tubes) to direct as much of the reflected light as possible into the tank. That will help even out the photoperiod for the tank as the sun moves across the sky.
VegasReefer
Premium Member
Bell Reflectors at the end of a solatube is purely for decoration.
The usable photons are traveling down the tube, at angles between 0 and 45 degrees anything bouncing of the tubes surface at an angle higher than 45 degrees will be hitting the water surface at an angle of over 45 deg and simply be reflected.
The bell reflectors round shape would work great if the photons somehow made a 180 degree turn just after passing bast the end of the tube.
You can however add a funnel shaped attachment that would have an angle of 30 - 40 degrees that is 1/4th the diameter of the tube ( IE 16 inch tube, 4 inch funnel ) that would redirect 45 - 70 degree photons 15 - 45 degrees back into the tank. I don't know if that would add enough output to be worth the trouble of measuring, cutting and affixing the cones to be worth while. though it might be an interesting project to use to tie multiple cones together.. Maybe I should get the CAD out and figure out how to do that for a 8 x 14" set up for a 120 x 48 x 28 700 gallon I have planed..
If I get a chance in the morning before I go to work, I will draw up what I am talking about, and show how/why it would work.
The usable photons are traveling down the tube, at angles between 0 and 45 degrees anything bouncing of the tubes surface at an angle higher than 45 degrees will be hitting the water surface at an angle of over 45 deg and simply be reflected.
The bell reflectors round shape would work great if the photons somehow made a 180 degree turn just after passing bast the end of the tube.
You can however add a funnel shaped attachment that would have an angle of 30 - 40 degrees that is 1/4th the diameter of the tube ( IE 16 inch tube, 4 inch funnel ) that would redirect 45 - 70 degree photons 15 - 45 degrees back into the tank. I don't know if that would add enough output to be worth the trouble of measuring, cutting and affixing the cones to be worth while. though it might be an interesting project to use to tie multiple cones together.. Maybe I should get the CAD out and figure out how to do that for a 8 x 14" set up for a 120 x 48 x 28 700 gallon I have planed..
If I get a chance in the morning before I go to work, I will draw up what I am talking about, and show how/why it would work.
mborn
New member
Perhaps in theory. But I’ve made bell reflectors for my tubes and have had them installed for a couple of weeks and they do increase the overall brightness of the tank, especially in the pre-noon morning hours and later in the after noon when the sun is lower in the sky and not directly overhead. They also have helped even the light out as the day transitions from morning to late afternoon. I’ve had my tubes without reflectors for 3.5 years and I can definitely see the improvement with the reflectors. So in actual application they provide a bit more than just decoration. The effect isn’t hugely dramatic though (i.e. it won’t make the difference between the tubes working or not working), but they are an improvement and worth doing IMO. As to which shape is better, bell or funnel, that’s an interesting question. I think the bell is sort of funnel shaped, albeit a curved funnel, but it might be worth looking at if a straight funnel is better than a curved one. As far as all the light greater than a 45 deg angle reflecting off the water, I assume that would be true if the surface was perfectly flat and smooth, but with all the current in my tank, the surface is constantly rippling and agitated, so I doubt that most of it is just reflecting off. But if it is, maybe some of it is getting caught and reflected back down by the bells.
8BALL_99
New member
I ended up not installing my skylight because I found a nice 3" pvc line running right where it needed to go. There just wasn't any way to move it and have it keep the same fall or slope on the line. So I ended up getting 3 14" Sola Tube brand tubes.. They were small enough to fit by the pipe but still sit pretty centered over the tank. I got them installed yesterday. Well more like last night. It took pretty much all day. Here is a couple pics from last night. I lined the top of my upper canopy/light shaft with FRP before I stalled the inside tube and trim.
8BALL_99
New member
Fiber Reinforced Plastic, Its the same stuff that my entire equipment room is covered with.. Its a plastic wall board thats used in commercial kitchens and bathrooms. Its just to water proof the ceiling. I plan on covering the inside of the upper canopy with it also. Sheetrock and moisture don't go well together
8BALL_99
New member
I took some pictures this afternoon around 5. I also checked the par. At the end of the tube I was getting anywhere from 500-800 par. But you move the par meter down 15" or so and it drops to 200 or less. When the light exits the tube it seems to shoot side ways and where else. I think if it was directed down the light output would be much better.
hahnmeister
In Memoriam
If you get the tubes close to the water surface, that will 'bend' the light downwards more... raising the intensity. Rays that enter the water at 45 degrees from vertical will be at 30 degrees from vertical underwater... the water surface itself acts as a lens. Since the light rays will be closer to vertical underwater, this will concentrate them more, but at such an angle, the glass sides of the tank will also act like reflectors... another bonus.
But considering you are getting close to 200 at 5pm, I wouldnt worry much... you might have much more than you need. What are the readings like at noon?
But considering you are getting close to 200 at 5pm, I wouldnt worry much... you might have much more than you need. What are the readings like at noon?
8BALL_99
New member
Dont know I was at work at 12. The 200 Par though is with in 15-20" of the tubes you move down and the par drops. It was very nice to see that 500-800 right at the ends though lol. I would like to get around 300 to the bottom of the stand. I see what your saying though about the water acting as a lens itself. I plan on either extending the tubes or adding panels with mylar or something like it to the upper canopy at an angle to direct the light down. I'm still trying to decide how to finish it out. Right now I'm thinking that I'll add a 16" extension to the tubes and then maybe try to add a small flare to the end of the tubes to help direct the light down. I dont' want to bring the tubes down to close to the water because I like having easy access to work in the tank. My upper canopy is about 22" tall the lower is about 19" They overlap a couple inches so from the top of the tank to the bottom of the tubes I've got about 40". So even with the 16" extension Your still talking 24" away from the tank. So I think some kind of ring to reflect the light down would help. Ofcourse these things will be inside a canopy painted white and maybe even covered with reflective metal so most of the light has to go in the tank at some point.. The biggest concern I have with that is the back of the lower canopy is open the equipment room. About 15" worth.. Hope all that makes since its a little hard to explain.
hahnmeister
In Memoriam
As for the 'ring' to direct the light... you might want to consider that the light coming down the shaft in these things is alot different than a bulb in a relative shallow reflector...
The light isnt from a point source, but enters at all angles (a). As the light comes in at a more and more of an angle... it will bounce off the sides of the 'tube' more and more... every time it does it will lose some of its intensity... say... with some miro that is 95% reflective... after hitting the sides of the tube a dozen or so times... you can lose a good percentage of the light coming in (an argument that the further north you are, the more you might consider having your sola tubes come down at an angle... perhaps the average angle of the sun at noon as it varies throughout the year... so you have more direct light).
If you decide on adding a 'ring' of reflective material to help guide the light downwards, also consider that since this isnt a point source light, like from a bulb, having a curved reflector is rather pointless. If you have a 'spherical' shape (b), you arent helping the light that hits the ring towards the bottom since its almost parallel with the sola-tube.... so what's the point? With a 'parabolic' (c), you have much the same, but at the top of the reflector... light that hits it at a sharp angle will still exit at a sharp angle. So the best 'average' is actually just a flat sided funnel (d)... which is nice because its the easiest to make. It will bend the most light downwards, and by making it 'flat sided', you can even have the angle be adjustable (so you can vary the funnel walls from say.... 45 degrees to 30 degrees) by having the bottom edge overlap and be adjustable with clamps (top edge stays the diameter of the sola tube, bottom diameter can change in diameter... like an aperture on a camera).
The light isnt from a point source, but enters at all angles (a). As the light comes in at a more and more of an angle... it will bounce off the sides of the 'tube' more and more... every time it does it will lose some of its intensity... say... with some miro that is 95% reflective... after hitting the sides of the tube a dozen or so times... you can lose a good percentage of the light coming in (an argument that the further north you are, the more you might consider having your sola tubes come down at an angle... perhaps the average angle of the sun at noon as it varies throughout the year... so you have more direct light).
If you decide on adding a 'ring' of reflective material to help guide the light downwards, also consider that since this isnt a point source light, like from a bulb, having a curved reflector is rather pointless. If you have a 'spherical' shape (b), you arent helping the light that hits the ring towards the bottom since its almost parallel with the sola-tube.... so what's the point? With a 'parabolic' (c), you have much the same, but at the top of the reflector... light that hits it at a sharp angle will still exit at a sharp angle. So the best 'average' is actually just a flat sided funnel (d)... which is nice because its the easiest to make. It will bend the most light downwards, and by making it 'flat sided', you can even have the angle be adjustable (so you can vary the funnel walls from say.... 45 degrees to 30 degrees) by having the bottom edge overlap and be adjustable with clamps (top edge stays the diameter of the sola tube, bottom diameter can change in diameter... like an aperture on a camera).
8BALL_99
New member
hahnmeister, You read my mind. Thanks for the illustration. I was already thinking of a funnel with flat sides. Just by looking at the outlet of the tube I was thinking this might be the most effective. Not to mention something I could make. I already bought some poster board on the way home from work the play with the angle and size before I try to do it out of metal. I also double checked my measurements and 24" extensions will work Perfect as far as the canopies are concerned. If the funnel reflectors comes down very much I might end up cutting the extensions down a couple inches, But I'll deal with that when I get that far.
Will
Will
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8BALL_99
New member
I've already made one out of Poster board. I'm waiting on my 24" extensions now. Once I get them I'll make my funnel out of metal. I need to find a good place to order the metal from. That or I'll just go to lowes or home depot and pick up a Extension tube for their brand solar tubes and cut the funnels out of that metal.
hahnmeister
In Memoriam
LoE filters UV as well as IR.
salty joe
Active member
I don't know how much LoE would knock off PAR, but judging from the light coming through my windows, it would be significant.
So I'm wondering if there is a filter that would block only IR, to be used only in the summer. Trying to find every possible way to cut down on the energy consumtion of my future tank.
It is my understanding that UV exposure can cause corals to produce protective pigments that are colorful. I also wonder if the UV might harm fish since they will always be in shallow water.
So I'm wondering if there is a filter that would block only IR, to be used only in the summer. Trying to find every possible way to cut down on the energy consumtion of my future tank.
It is my understanding that UV exposure can cause corals to produce protective pigments that are colorful. I also wonder if the UV might harm fish since they will always be in shallow water.
DheereCrossing
New member
Most metal hailides with out filters give off uv don't they?
