DIY 125 Gallon Aquarium Stand

Today I started construction of the 125 gallon aquarium stand. Using plans I found online construction was actually quite simple, at least so far. There are a couple of snags but overall it is turning out well. The weather is fantastic this week so I hope to have the majority of it completed soon. Today I went from just a stack of raw lumber to a nearly completed frame.

The stand size will be 72 1/2″ long, by 18 5/8″ wide, and 30″ tall (30 1/2″ when the plywood top is factored in).

The first step, of course, is getting all the tools together. Take note of what’s pictured at the top, safety glasses and ear protection. Don’t skip on it, you’ll be thankful.


Basic Tools

First up was cutting the plywood for the top that the aquarium will sit on, and for the back which will provide extra support from the stand rocking. Pictured below is how I recommend cutting sheet goods, use some 2x lumber to keep the large 4×8 foot sheets straight, otherwise you’ll have a dip between the sawhorses making your cut less than perfect. I should of taken a picture of how I set up the actual cuts, but I forgot :S

An easy way to get a straight cut on a huge sheet of plywood is to clamp down a 1×4 or 2×4 that you can use as a fence, like you would on a table saw. In fact, instead of a circular saw you could use a table saw if, and only if, you have a fence that you can set wide enough for the cut.

Sheet Cutting

Plywood Sheet Cutting

Next up is cutting the 2×4 and 2×6 lumber. I happen to have a miter saw which makes easy work of this task, a radial arm saw can also do it quite easily. If you must, you can use a circular saw or table saw but that isn’t ideal. If I had an actual work bench I could have set up a jig to save myself substantial time, but I still got the job done in not too much time.

Miter Saw

Miter Saw

Cut Lumber

Cut Lumber

After that, it’s just a mater of screwing it all together. I used 2.5″ exterior screws, with a square drive. In addition, I used a countersink bit before using the screws to ensure I would have a flush finish. This is particularly important because I plan on skinning this stand in oak to finish it and you do not want screw heads giving you an un-even surface.

Countersink Screws

Countersink Screws

Flush Screws

Screws Are Flush to the Wood

Below you can see several pictures of the frame as it progressed. Basically it is just a bunch of 2×4’s in a typical frame, however the top box is made of 2×6’s for added strength. The 2×4’s on the inside of each corner are only there as a surface to attach the corners to and keep everything square, they serve no structural purpose which is why they do not extend all the way up to the top. If they did extend all the way to the top, they would take a portion of the load and I really don’t want screws to be supporting part of the load, I want it all going into the 2×6 box frame, then the vertical 2×4’s, followed by the bottom 2×4 frame, and finally the floor.

Top Box Frame

Top Box Frame - 2x6's


Stand Legs

Starting to assembly the legs to the stand

Basic Frame

Basic Frame

The above basic frame picture is actually all you would need to support the 1400 – 1600 pounds. I know, it looks terribly open, but by the math according to structural engineers it’s true. At the very least you want to put plywood sheeting on the back and the sides to keep it from rocking, that will take the tank down to the floor in no time if it isn’t supported in left/right or forward/backwards directions.

To facilitate the addition of doors to the front, and to ensure more uniform load to the floor I added two more center supports. I also added some short pieces to the top that I’ll nail the top plywood to, and also ensure the frame dosen’t twist over time.

125 Gallon DIY Aquarium Stand

125 Gallon DIY Aquarium Stand

It’s far from completed but that’s where I am after day one, not too bad. I still need to put the plywood sides and top on, get the inside plywood shelf made and that will complete the frame. After that I need to skin it in oak to give it a nice furniture look instead of the utilitarian look it has now. I’ll be sure to post progress updates as they happen.

Thanks for visiting!

Custom LED Aquarium Light Fixture

I finally put forth the effort and spent the time to finish my custom LED light fixture. Originally I had planed on using three LEDs, but after seeing how bright the first one was, I went with two this time. The tank is noticeably brighter than before, as expected. So now time will tell if the lights respond well to the new light, and if algae becomes a problem from the increased intensity.

For reference, you can view my original post about the building of the first LED here. Each LED is at a color temperature of 5665K and outputs roughly 700 lumens each. In equivalent fluorescent lighting this gives me about 1.4 watts per gallon which doesn’t seam like much on the surface, but it looks brighter than that. In fact, it looks brighter than our 10 gallon that has 2 watts per gallon and not nearly as tall.

Crossing our fingers we don’t have an algae farm!

Custom DIY Aquarium LED Project

I’ve started a prototype DIY LED project which is basically just a proof of concept to see if the idea is even feasible and if I like the end result.

So here is some background, when I started my 20g aquarium I put in some plants, mostly of the low light variety. The tank only has a single 18″ T8 florescent tube for a light which is most certainly low light. My wisteria, which is suppose to be a fast growing plant, is actually growing quite slowly. In the future I plan on having a 120g aquarium that wouldn’t be much better off for light, so I was worried I’d have to upgrade if I wanted to do anything spectacular with my tank. The problem though is a 48″ dual tube T8 fixture is quite expensive, over $100 expensive. Yuck!

As an Electrical Engineer by day, I began to think, you know, I could make my own LED light fixture! I cost the project out, and it’s reasonable. Cheaper than any commercially bought LED fixture for sure. The LEDs themselves are only $5 each and each one produces the same lumen rating as an 18″ T8 bulb. Now, before you go running off to buy out the store of these super cheap $5 LEDs know that there is a lot of other stuff you have to buy in addition to the LEDs to get them to work!

You need a heatsink (these high power LEDs get HOT!), thermal paste, an AC/DC power supply, a constant current source, something to mount all this to, a pcb to assemble your circuit on, a power switch, a power connector, and all the various mounting hardware. And when you’re done, it will not look pretty unless you spend a lot more on a nice looking enclosure (or are handy with woodworking/metalworking and can make one yourself). Now, me personally I don’t care about aesthetics, at least not on my prototype project.

So, without further blabbing I’ll show some photos of the project so far. It is still a work in progress. This first photo shows you the LED itself mounted onto a blank anodized aluminum heat sink. Ignore the screws with their heads broken off. Pretend they don’t exists… and ignore the bad solder job, I learned the hard way to solder before attaching to the heat sink next time ;) If you don’t understand why, it’s because you need high heat to melt the solder, which comes from the soldering iron. But if you have a huge heat sink attached … you guessed it, it is much harder to get it hot enough to melt the solder! Lesson learned, I’m an engineer, I work on theory and paper, not a tech who actually builds the stuff I design =)


Closeup of LED

The brightness of an LED is a function of the amount of current going through it. The higher the current, the brighter it is. However, the higher the current, the hotter it gets and the hotter it gets, the lower its lifespan. For this particular LED a current of 350 mA will produce an output of 685 lumens at a color temperature of 5665K, for comparison an 18″ T8 6500K fluorescent tube is 700 lumens.

The current however is variable on many things, it depends on the input voltage, it depends on the value of a current limiting resistor, and it depends on the temperature of everything. In short if you just used a current limiting resistor with a DC power supply you would not have a constant, predictable current and thus brightness among all your LED elements. To solve that, you need what is called a constant current source, and if you can’t guess what that does I can’t help you ;) Below is a picture of the circuit I build following directions online (why reinvent the wheel?). It is simple and fairly inexpensive to build, but is not all that efficient. I plan in the future to try making a much more efficient design, but it would require a custom PCB which is very expensive to do.

LED Driver

LED Constant Current Source

See, pretty simple, just two resistors, two transistors, and a zener diode.

Okay, enough talking, here it is in action. The first photo is a picture under the 8000K fluorescent light I have, and the second is the 5665K LED (only a single LED, I plan to have 2-3 of them). You can clearly see the difference in color spectrum, but brightness wise I’m impressed on what that single LED can do!

Normal Light

Normal 8000K 18" T8 Fluorescent

Single LED

Single 5665K LED

Feel free to leave comments with any questions! I know the number one thing people will want is a schematic… I’ll think about it, but that would require me to draw it up and I’m quite lazy ;)