Sealing the seams: I felt the best way to seal the seams, was for there to be no seams at all. I wanted
to make the interior of the tank one solid piece, and what better material for the job than fiberglass?
I would seal all the corners with seam tape, and then lay several layers on the walls and bottom of the
tank. On top of this, I would roll several layers of 2 part epoxy to add color and finish sealing the
Once I had the general idea of what I wanted to do, things really got tricky. I had to settle on a final
tank design, choose and locate all building materials, design/fabricate filtration, figure out how I would
heat/cool the tank, lighting, etc. etc. To make matters worse, was determining how to deal with
approximately 14,000 lbs of water weight, and preventing the humidity caused by evaporation for destroying
I had witnessed tanks fail in the past, due to being unlevel, or being on pillars which allowed different
points of the tank to move at different rates. At that point I decided my tank must not only be built
on one solid slab of concrete, but also sit directly on the ground. My house was built over 12 years
ago, so I knew the concrete had time to settle. I found that my concrete floor in the basement was over
6" thick, and the slab on which I intended to build the tank was level and free of cracks. At that
point I concluded that my floor would support the weight, and was ready to begin construction.
I started rough sketching the tank and once I had a decent design, I went at it. The dimensions are as
follows: 104L x 66W x 57D, External 122L x 82W x 64H. As stated before, there would be no stand as I
wanted the tank to float/settle with the slab on which it was built, plus I needed the headroom above. So
construction began. I first laid the four outermost 4x4's. I cut down the side pieces from their 144"
overall length, to roughly 128". I did this only to ensure that the tank would not overlap onto the
next slab of concrete. The end pieces were cut at 86", and would fit in between the side pieces. The
limiting factor on the width of the tank was not the concrete slabs, but rather the tank had to line up
with a wall I would be build, and I figured I needed at least 36" behind the tank. The four boards were
then bolted together using 1/2" x 9" lag screws. All holes were pre drilled 3/8" dia, to approximately
90% depth, and then countersunk 1.5" dia x .5 deep. The counterbores would allow for the 1.5" dia
washers and the head of screw to be recessed into the wood. Note: All lag screws used on the tank
were installed in this same manner.