Aquascaping is fun, but not an easy task. I’m pretty happy with what I managed in my 90g, but this tank is a little bigger. I’m also working with over 300 pounds of rock.
I really don’t want the rock sitting on the glass and buried in the sand. In my opinion, this causes a whole set of problems not the least of which is an unstable base structure. Instead, I want the rock elevated slightly above the sand. Amongst other things, this should help to ensure good flow while creating additional caves and shelter for various fish and inverts.
To accomplish this, I envisioned a peg board style base where I could plug acrylic rods wherever they were needed. If I wanted to move a rock to a different location, I could just move the pegs. Depending on the size and shape of the rock, the pegs can be inserted in a variety of combinations.
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The rock above is supported by this peg configuration:
Assembly
There are two acrylic sheets.
The bottom layer is ¼” and does not have any holes drilled in it. The purpose of this sheet is primarily load distribution to avoid the effect of point loading.
The top layer is ½”. This layer has to be thick enough to provide adequate support for the pegs.
The pegs are ½” acrylic rod. The pegs are friction fit into the holes and are not glued in place.
The two sheets of acrylic are bonded together with Methylene Chloride. This was actually fairly easy to do. I simply used a syringe applicator to circle around the bottom of each hole and the sheets bonded together. I completed this step in the tank as I wanted a flat surface to work on to ensure the acrylic didn’t warp.
Construction
A grid was drawn. There are more holes towards the back. Spacing was 1”, 2”, 2.5”, 2.5”, 3” and repeating. The idea is that rock will be denser towards the back of the tank.
Drilling the holes was more tedious than difficult. The biggest challenge was keeping the drill straight. Not all of the holes are perfectly vertical but, other than aesthetics, I don’t see this as a problem.
That’s a lot of holes. Notice the third row at the back. I drilled these holes just for good measure.
Having put the acrylic sheets into the tank, this was my first trial.
One of the problems that I wanted to avoid was having sand get between the acrylic and the glass bottom. I cleaned everything the best that I could and then siliconed the acrylic to the glass around the edges. I know that silicone does not bond well to acrylic, but I also know from experience that it does bond well enough when there is no pressure or stress on the seam. In this application, the weight of the rock will help to keep the sheets in place and the silicone is really only to keep the sheets from sliding and sand from getting under the acrylic. I used the weights to hold the acrylic in place while I was applying the silicone to ensure that there were no gaps.
Conclusions
One obvious limitation of this approach is that it is really only suitable for tanks with a sand bed. It also costs a fair bit of money. Having said that, I am really happy with the final product and am now looking forward to aquascaping.