Alex Camacho
Crosby, TX, United States
Born in Houston, Texas and raised all over living the life of an Army Brat. I Went to eight different schools (three elementary, one middle school, four high schools) and have one little brother who’s not so little anymore. I’ve been married for nearly fourteen years now to a woman who rocks my world and I've been blessed with two wonderful children. Our dog, Sally, is a big black lab saved from a local shelter.
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Sunday, May 23, 2004

Aquarium Background

This is a repost of a DIY aquarium background I built for my 120 gallon tank back in 2004. When I decided to drop my domain host I lost the page it was hosted on. After having gotten numerous emails over the years I decided to repost it through my blog. For the most part, its just a copy and paste job so I can't promise the numerous sites linked to back then are valid.

So for those of you who asked for it, here it is - again...


rebuild2_tank03aNever being able to leave good enough alone, I decided the tank needed a change from the first rebuild. I wanted to add a level of realism to it that I felt was missing. I wanted something that looked a little more natural and increase the level of water in the tank. So I hit the web and did a little homework. I found tons of great sites but the site that really started it all was Chuck's Paludarium. It seemed pretty simple and I already had most of the stuff laying around the house from other projects and with the tutorial on Chuck's site as well as others (check the bottom for more links) I knew I could tackle this.

The concept was pretty simple. Create a realistic background for an aquarium using polystyrene sheets and marine epoxy. The wall would serve two purposes. 1) be aesthetically pleasing to look at and 2) hide all the stuff that detracts from an aquarium's appearance (pumps, filters, heater, etc.). Here's a list off all the stuff you'll need if you plan on doing this:

Tools Supplies
  • Measuring Tape
  • Pencil
  • Utility Knife
  • Mini Hacksaw
  • Soldering Iron
  • Surform Shaver
  • Duct Tape
  • Sandpaper
  • Mixing Buckets
  • Power Drill & Paint Mixer
  • Caulking Gun
  • Stainless Steel Ruler
  • Acetone
  • Putty Knife
  • Pencil Sharpner
  • Expanded Polystyrene
  • Super 77
  • Dowel Rods
  • Latex Gloves
  • Great Stuff
  • Disposable Mixing Cups
  • Paint Brushes
  • Nipples & Hose
  • Window Screen
  • Portland Cement
  • Latex Paint
  • Two-Part Marine Epoxy
  • Sand & Pebbles
  • Silicone
  • Plexiglass
  • Acrylic Solvent
  • Popsicle Sticks
  • Rio Pump 1400

Step I: Gluing & Carving Polystyrene
rebuild2_island01a
rebuild2_land06
I knew what I wanted. I wanted a rocky background with an eroded land formation (which would have a small waterfall) on the right that came out of the background and an island formation on the left attached to the bottom glass panel. So I measured out the dimensions of the two pieces, began cutting out squares of polystyrene, and gluing them together with Super 77 until I got the size I wanted. This was to be placed on the left side of the tank. It was pretty simple to carve other than the glue always giving in the middle. This is the land portion that's going to be attached to the background on the right side of the tank. Lots of cool caves that go all the way through and a stream that ends in a waterfall. From there I started cutting away with the mini hacksaw and got the rough shape right with my sureform shaver. Once I had the general shapes right, I plugged in the soldering iron and opened a window with a fan propped up to suck out the air. This stage of the project really sucks. This stuff stinks when it burns. I wouldn't recommend trying to do it all at once unless you wanta major fumes headache. Take frequent breaks. The island gave me some trouble as it kept coming unglued but the eroded land came along great. To make the waterfall/pump output and caves I just pushed the soldering iron through all the way. Pretty easy work, but took a lot of time. I liked chuck's idea of integrating a piece of bog wood into the background so much I did the same for my eroded land piece. The island kept coming unglued in the middle. I think I made it too thin there and the weight, even though light, just was too much for a thin middle to support. I tried more Super 77, Concrete Patch, and Liquid Nails. It finally held when I inserted two dowel rods running vertically through it. Or so I thought... A tip to others; Don't try the island thing with polystyrene. It didn't work out, but I'm stubborn so I tried to make it work all the way to the bitter end. Once you're happy with the general appearance, break off all the hard plastic edges that the melting polystyrene makes and soften the edges for an eroded look with light grit sand paper.

Things I'd do differently
1. I wouldn't make an island structure out of foam. Trust me on this, it doesn't really work.
2. I'd make my cave structures on the land portion a little bigger and make the stream deeper.

Additional Photos:
rebuild2_island02rebuild2_island03rebuild2_land02rebuild2_land03rebuild2_land04rebuild2_land05


Step II: Plexiglass & Great Stuff Foam
rebuild2_halfway01a
rebuild2_halfway02a
Once I had the pieces constructed I measured the inside dimensions of my tank so I could cut the background piece of foam. I was hoping I wouldn't have to make the background into separate pieces so I took about an inch off on both sides and an inch and a half off the top. I really didn't want a seam line on my background. I was hoping that when it was all complete I could squeeze it in as one piece. Did I mention I'm stubborn? So Once I measured the piece, I cut it out with a utility knife, then I squeezed it in to make sure it fit (which it still did at this point). Since I had ordered my Rio pump through Aquadirect but hadn't got it in yet, I made a cardboard box in the pump's dimensions. I put it in the tank with the newly cut background and measured out that I would need around three inches in the back for the filter to fit. So I glued together a big block of polystyrene matching the height of my tank and cut all the spacers I needed, then glued them to the back. In this photo you can see how I attached the land portion to the background. After I glued it into place I simply took three 3-inch machine screws and screwed them all the way through. Here it is waiting for cement mix to be spread over it. Once that was done, I then took my four cans of Great Stuff Foam and sprayed it on. I made sure to get all around the land portion and a little underneath it to help strengthen the bond to the background. Great Stuff Foam needs twenty four hours to fully cure so I moved on to making the filter box. Since I had at least three inches behind the background I made my filter box 3x3x12in. So I used the acrylic scoring knife and the ruler to cut my pieces. Duct tape is great for holding your cut Plexiglass in place while you apply the Weld-On. The holes in the middle dividers to allow water to flow from one chamber to the next were made with my soldering iron first, then glued in with the Weld-On. The holes for the water intake nipple and water outflow nipple I actually drilled since the hole diameter was too big to get a good circle with my soldering iron. Once it was all glued together (Weld-On sets pretty fast) I put the nipples in place and ran a bead of silicone on the inside and outside for a watertight seal. I constructed a top to the filter but it never really fit right. The next day, after the foam had set, I tackled the job of "texturing" it. I had experimented before trying this and found that by tearing away the top layer of hard foam, then lightly painting on cement gave a really great rocky appearance. So I began tearing away at the hard foam creating crevices and little out shoots. I enlisted the help of a few friends here, but it didn't keep my fingers from being sore for days afterward. That foam is pretty freakin hard! Then I test fitted it to my dismay. It wouldn't fit with the spacers attached and my land piece came out about an inch and a half too far. Like most large tanks I have a support bar in the middle of my tank. I wasn't feeling ballsy enough to remove it and re silicone it back so I shaved off some of the island, split the background down the middle, and added another spacer, then placed the filter box holder piece into place with Super 77 and dowel rods sharpened to stake ends with a pencil sharpener. It fit! Lastly, I made the holes for the water flow. One on the bottom left side and another on the bottom right side. I also decided to take off about three inches off each spacer on the bottom except for the far left and far right one to increase water flow.

Things I'd do differently:
1. I'd definitely make the filter box taller for more water capacity. Probably something like 6x3x12.
2. Rather than use machine screws to help hold the land in place, I'd just use dowel rods. I'd push them all the way in, remove them, take off about an inch of the dowel rod, inject epoxy into the hole, then push the dowel rods back in. It would be a much more secure attachment.
3. I'd dowel rod the spacers on as well using the method mentioned in 2. They kept coming unglued in some places.
4. Once the Great Stuff Foam was cured, I'd take the Surform Shaver and make sure the bottom was flush and even with the background polystyrene.

Additional Photos:
rebuild2_halfway03rebuild2_halfway04rebuild2_halfway05


Step III: Cement, Paint, & Epoxy
rebuild2_epoxy01a
rebuild2_epoxy02a
This was by far, the messiest part of the whole project. Mix up small batches of cement as it'll dry pretty fast. I used one of my mixing buckets and a spatula. You want it about the consistency of thick paint since that's exactly what your going to do. When you begin painting it on, make sure you seal up all the holes exposing the background polystyrene and fill in all the little air pockets in the foam. The island after it's paint job. It looked really great so far... The background after it's third coat of epoxy. I started with a different epoxy and switched to a lower gloss epoxy by West System.I put on around three coats of cement I think. For the really big holes in the foam I just smeared concrete patch in. To make the seam line as invisible as possible, I smeared concrete patch in the crack, waited for it to start harden, then separated the two pieces. Concrete patch is very pliable and once it starts to set, it's pretty easy to reform. Once I was done applying cement and concrete patch, I had to wait for it all to dry. So I painted. I took black latex paint, poured what I needed for both the island and the whole background piece into a bucket, and mixed in primer white until I got the gray base color I wanted. I used my power drill with a cake beater attached. It worked fine even if my wife did object at first. The reason I mixed all the paint I needed was so I would keep color consistency throughout the painting part. Like miniature painting, you should primer first, add your base, add your darker wash, then dry brush a couple layers of light shading. I gave the paint a day to dry then I mixed up my first batch of epoxy. Wear gloves and the crappiest pair of paints you got along with an old concert shirt you're wife hates, preferably long sleeves. Getting epoxy in your leg or arm hair sucks, trust me. I mixed about half a cup each time. It may not seem like a lot but remember it's being painted on. Also, the West System Mini Pumps made measuring a snap. One pump of each, then mix it good with a popsicle stick. I used about three or four pumps each mix. I had to use a gloved hand smeared in epoxy like lube to get the caves and water outlet holes well covered. I could use other similes to get my point across on how to do this but I think you get the point. I've found the "come here" finger motion works best... Once I had a good couple layers of epoxy on, I put a thick layer on the tops of both the island and the land, then sprinkled sand on top. Once that was set, I did that a few more times with pebbles and gravel. The last thing I did was place the window screen with silicone.

Things I'd do differently
1. With all the expanding foam and the curing cement, I found that polystyrene will warp ever so slightly. It made my seam line hard to hide. I would go with a plywood next time.
2. I'd use a more flexible hose for the pump and filter box. It would just be easier to work with than the stuff sold at Lowe's as "Aqaurium Hose".

Additional Photos:
rebuild2_epoxy03rebuild2_epoxy04rebuild2_epoxy05



Step IV: Installation
rebuild2_installedThat's all there is to it!! From there I installed. I used plenty of silicone but I made sure none of the silicone made contact with the tank silicone so I could remove it later if I wanted without having to patch my tank's silicone. I did do something most will probably disagree with me on though. Once the epoxy was applied, it was shiny. I mean like rolled-of-the-car-lot shiny. I shopped around and found a clear acrylic sealer matt finish and sprayed on a light coat. I was pretty sure once it completely cured it would be non-toxic but I wasn't sure. Turns out it's perfectly fine. It took the glossy shine right off. I used Duct Tape to hold it all in place until the silicone set completely. Then I filled it with water and watched my island (siliconed to the bottom pane of glass) tear at the middle and float up. I was mortified, angry, and too tired to fight it anymore. I turned on the pump to find that my stream was more like a ditch and the water was just cascading down. So I drained the whole thing with the pump, chipped away at the epoxy and concrete ditch, and made it deeper (all from inside the tank since it was all siliconed). Then I patched it all up again with cement, painted it, and resealed it with epoxy. Fun huh? It was worth it though because the water actually follows the stream now while a little cascades down the side. The filter box worked out great too. In chamber one I filled with filter sponge, in chamber two with ceramic rings made by fluval, and in the third one I put activated carbine. I ran the filter for a full day before I put in my fish and animals. I had to adjust the flow rate of the pump down a little to keep it from overflowing the filter box, but it worked out fine. The three pieces of wood were siliconed down.

Things I'd do differently
1. I think next time I'm not going to use the Marine Epoxy. With each coat I applied I watched my shading disappear from the rocky surface.
2. I'd use tinting pigments in the cement for shading on the rocks and use a "rubber stamping" method to create the texture (see below links).
3. Next time I'm going to have a largish spare tank to house my fish and critters in. They were kept in a large tote the few weeks of construction and my crab sniped a few fish that came into his tree lair.

rebuild2_tank01a

Overall, I'm satisfied with how it came out. The fish like their new home and they have a lot more room then they ever did before. Cleaning it has become a breeze and my filter box is very accessible. I did have to construct a frog guard out of Plexiglass to keep the toads, newt and crab from getting behind the background.I just took the scrap pieces from the filter box, made 3x12in pieces, glued them together to make one long piece, and siliconed it to the background leaning forward like a barbed wire fence does. Again, duct tape to hold it in place until the silicone set.

I've already got plans for next year and I got a bunch of other tanks to experiment with until then. It really was pretty easy to do once I got off my ass and did it. If you got questions, just shoot me an email and I'll be happy to answer any questions.

Now to give credit where credit is due. All these links guided, informed, or inspired in some form or another. These guys rock for there contributions.

Now to give credit where credit is due. All these links guided, informed, or inspired in some form or another. These guys rock for there contributions.

Chuck's Paludarium
A truly inspiring tank setup. My primary source of inspiration. A very informative site as well.
Paul Barber's Background
Another great source of information. No marine Epoxy just pigmented cement and it's aquarium safe!!
Catfishheaven.net
A very detailed day by day account of construction. Another cement background with no marine Epoxy. Next time...
Kyle Porter's Background
A simplistic, but nice looking background. Easy on the wallet for a nice looking background.
3-D background
No author listed on this one. Very informative but no pictures.
Brad's Cave Grotto
I like the idea behind this one. Creates lots of caves and is very simple. Again, easy on the wallet.
Reptile Rooms
A lizard link, yes, but a quick method of getting a rocky background that could easily be improved upon.
PU Background
I'm not really wild about this technique, but here it is. I personally don't like the rock look but that's just me.
Concrete Stamping
Not a aquarium link, but I think this is how a lot of "professional" background makers get there great results from.
Geodesic Foam Scenery
While not a aquarium link, this technque could be used for a background I think. It's my next project to try.
Rock Texture Pads
Again, not a aquarium site but this could be used to make very realistic rock backgrounds just as the previous link.
Aquarium Background
Don't want to look at another DIY background and would rather just whip out your wallet and buy one?
Back to Nature
Another online store that sells great looking backgrounds. Notice the same techinque of "stamping" the texture.