440 Gallon Custom Drop-Off Reef Tank

You mean I shouldn't have installed it over the carpet? Really???

LOL No, Stouty109, I ripped up the carpet and padding, removed the baseboard, scraped it all down to bare concrete, swept and mopped about 20 stinkin' times, coated the bare floor with an acrylic primer, then laid down the planks. Really came out great, and you'd never guess it was anything other than actual hand-scraped walnut.

Yeah, I'm really looking forward to making that mini-tank. I'm going to try to mirror the big tank as much as possible.
 
Thanks, everyone. I've got to say we're pretty pleased so far, too.

Speaking of which, I've had a few people ask about how the big tank is being constructed, i.e.- why not make it the normal way, why build it this way, why not have AGE/Marineland/etc. make it. Here's why:
Beyond the issues of having to perfectly level the two levels in order to achieve a perfect silicone bond without weak points (if you were to build it the normal glass/silicone way), the other reason it's being siliconed directly to the steel, much like a large-scale commercial aquarium. And no, unlike some people have thought, you don't want it to give, to do so introduces shear forces upon the silicone seal. Ideally, you want to silicone directly against the most stable outer surface as possible, so that the only force being acted upon the silicone is compressive force, where the silicone acts merely as a packer and seal, rather than being held in tension or shear, as most silicone and glass aquariums are. Utilizing silicone in this manner is almost incalculably stronger (assuming a strong outer surface, i.e.- strong welds and well-built structure, to seal against) than utilizing silicone as an adhesive. Not only that, but then your safety factor relies on the strength of the glass between the steel frames, rather than upon the strength of the silicone bond (either in tension or in shear) to retain the shape of the glass and keep it from reaching the point of failure due to deflection. Remember, when calculating required glass thickness, the biggest issue is bending stress, so supporting the top and bottom of the pane of glass reduces (almost to the point of removal) that bending stress at the point where it's most likely, i.e.- the top and bottom shear-held silicone bonds. Really, the only issue relative to the use of metal for the frame is the differential linear coefficient of expansion between glass and most metals, especially steel. To offset this in larger joints (i.e.- those longer than 1 meter on their longest edge, or a bit over 2 meters in this case) the thickness of the silicone seal must be changed to allow linear expansion without the fear of compressive failure. Assuming that plate glass has a linear coefficient of expansion of ~5.0 x 10^6 in/in degrees F, and steel has a coefficient of linear thermal expansion of ~7.3 x 10^6 in/in degrees F, allowing 2-3mm per meter of joint length (i.e.- 5mm seal along the large side plates, and 3mm along the front plate) will allow the silicone to take up the linear expansion differences without failure of the silicone seal.
 
Make sure that you take tons of pictures when it comes to actually installing the glass and stand. It will help alot of people in the future.
 
Hey kroth0322, nope, not an engineer (well, not that type of engineering, at least). I spent part of my pre-military career designing fault-tolerant high-availability internet and database systems for the federal government and financial institutions. As for this stuff, just lots of research and trying to learn whatever I can... Thanks for letting me know I'm on the right track... Do you see anything I missed, or anything that seems "off" to you? Please let me know if you think I should change/improve anything in the design.
 
Last edited:
fjr_wertheimber said:
Okay, so here's the planned setup of the LED lighting for the tank. It will be built in a curve over the tank so as to mimic the natural change of lighting angles throughout the day, and allow gradual ramping up/down across the overall fixture for more gradual lighting changes. Well, that's the plan, at least. LOL
Click to expand...

drolic said:
Wouldn't it be a more efficient use of hardware to articulate the panel the LEDs are mounted to -vs- having more LEDs turning on (brighter) / off (dimmer).

Think about it like the opposite of a solar panel tracking the sun... the sun (panel of LEDs in this case) would tilt. What do you think 30 degrees off of center (flat / level) in each direction?

The shadows moving across rock work / corals throughout the day would be a cool effect. I know my SPS's have a 'bright side' / 'dark side' effect caused by uneven lighting.

I don't know the specifics of the apparatus but I am sure one could be constructed using VDM (0-10 vlts) output from a controller. -or- even more simple... pivot the panel from a a geared down motor on a timer.

It would / could obviously be synced with the panel brightness too. For example say it tilts 30 degrees to the 'right' at 8 AM with LED's being at 20%. At noon the panel would be flat (level) and LED's would be at 100%. At 8 PM, the panel would be at 30 degrees to the 'left' and output could be 20% again.

For bonus points... bring on heavy reds in the evening for a nice 'sunset' effect. :)

Have never seen it done before...
Click to expand...

First off, fantastic planning and great progress so far... nice to see another out there who puts an extreme amount of up-front thought into all this.

Reading through your thread is eerily odd for me! All design issues that I thought about and considered in my current LED build you are tackling on yours... One of my goals was to be able to cast shadows one direction in the morning and the other direction in the evening.

I originally started by thinking about a curved fixture like yours... But in the end, my form design goals "flattened" it (I didn't want to have a klunky fixture atop my tank), but left the strings at an angle toward center, then my manufacturability goals took the angles out and just put wide angle optics on it and programmed a moving Gaussian curve to the string of LEDs (I was working with a 2.5D CNC machine, so the angles would have been very tough to do without a lot of hand work)... I have yet to find out if the changes took out the ability to cast shadows, but it is fascinating to watch another tackle the same design problem in such a similar way. Here is my LED build thread, btw.

Also contributing to the eeriness, I just wrote an article for my local reef club about designing things to be more fault tolerant.

Weird.
 
Im really enjoying your build process :) its going to look amazing once done.

you last post made me think of facts ive never thought of before !

I always had the "dream" of same concept, but with dropp off going all the way to the floor level, and longer so I could have stingrays there, and SPS on the shallow side. so will have be following your thread if I decide to make my dream come true one day :)


thanks for sharing with us.
 
ChadTheSpike said:
First off, fantastic planning and great progress so far... nice to see another out there who puts an extreme amount of up-front thought into all this.
Click to expand...

Thanks, Chad. Awesome to see you following this build thread; I've been drooling over your DIY LED fixture for a while now. I've actually contemplated how to encapsulate the LEDs within a similar fixture while retaining the functionality and design I'm looking for. The LEDs will be enclosed in a hood, so I'm not (as) worried about how pretty the whole thing looks, or if it's clumsily large, as I would be if it were an open top tank.

Yeah, I've definitely spent quite a bit of time (too much, if you ask my better half... LOL) planning out this build. I'm curious to see how ramping up your LEDs works out for you the way you've got it. I had thought about doing so that way, but worried that for the size of the tank I'm building it wouldn't work.
 
fjr_wertheimber said:
Thanks, Chad. Awesome to see you following this build thread; I've been drooling over your DIY LED fixture for a while now. I've actually contemplated how to encapsulate the LEDs within a similar fixture while retaining the functionality and design I'm looking for. The LEDs will be enclosed in a hood, so I'm not (as) worried about how pretty the whole thing looks, or if it's clumsily large, as I would be if it were an open top tank.

Yeah, I've definitely spent quite a bit of time (too much, if you ask my better half... LOL) planning out this build. I'm curious to see how ramping up your LEDs works out for you the way you've got it. I had thought about doing so that way, but worried that for the size of the tank I'm building it wouldn't work.
Click to expand...

What you could maybe try if you have the tools available is to cut out stepped holes for optics in a piece of clear plexi and then heat treat that pice of plexi to bend it... that way you still get the arc but also are able to protect the LEDs and electrical components... I don't know.. just a thought.

I am looking forward to seeing more progress and pictures!
 
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