Being cheap by nature, I found it was much less expensive to purchase bare tanks rather than complete setups (tank, lights, hood). I’d buy a bare 55-gallon tank and use a standard fluorescent shop light fixture. However, I still needed an inexpensive tank cover that would allow enough light to penetrate for good plant growth and be easily customized to allow cut outs for heater, filters and other equipment.

A Solution

Several years ago when I moved into a new house, I found half a sheet of prismatic lens material. These 2 feet by 4 feet sheets are used as the lenses for fluorescent fixtures in drop ceilings. No doubt you’ve seen them before and haven’t given them a thought. I found that they make excellent and cheap tank covers and are fairly easy to cut and customize. You can find the material in home and building supply stores such as Home Depot and Menards. The lens material is usually located adjacent to the ceiling tiles. Building supply stores sell several styles of lenses. You want to find clear material with tiny peaks and valleys (see Figure 1). This material is commonly available in two grades; a basic grade and a deluxe unbreakable grade. Buy the cheaper material... I have found that the deluxe unbreakable material curls over time and is harder to work. I have spent as little as $2.00 for an entire sheet. If you don’t have to make a lot of covers, you can often buy a broken sheet for much less. By the way, you’ll find eggcrate material in the same location so you can pick up some on the same trip to keep your cichlids from killing each other.

Tools Needed

Each 2 feet by 4 feet sheet is enough to create covers for two 55’s or four 20-gallon tanks. You will need the following to create covers of your own:

• Sharp utility knife or acrylic cutter (see Figure 2)


• Metal square or T-square


• Work gloves


• Fine-point permanent marker


• Diagonal cutters or needle nose pliers


• Fine Sandpaper


• Hole saw and electric drill (optional)

Note: Like any other project involving sharp tools, there is a risk of injury. Please use care in following these instructions and wear protective eyewear. This is a project for adults.

Making Your Own Tank Covers

Follow these steps and you’ll have tank covers in no time:

1. Measure the inside frame of your tank and subtract 1/8" from both the horizontal and vertical dimension.


2. Place the plastic sheet flat side up on a hard surface like a large piece of plywood.


3. Use the ruler to carefully measure across the shortest dimension of the sheet (see Figure 3). Place a small dot with permanent marker.


4. Look carefully at the sheet and observe the pattern of the sheet. You will need to cut directly across the end points of the diamond pattern to avoid breaking the sheet when you cut it. This means you may need to adjust your cut slightly.


5. Lay the square on the sheet at your cutting point and make sure that everything is lined up to make a good cut.


6. Hold the square down firmly and score the sheet repeatedly with the utility knife (or acrylic cutter). When you feel the knife start catching in the material (penetrating the other side), you’ve done enough.


7. Grab the sheet and carefully flex it against a hard edge (like the edge of table) and the sheet should snap cleanly.
8. You may need to use the sandpaper to clean up the edge.


9. If you find that the cover is a too big to fit well, you can use the square and utility knife to score as little as 1/8" along one of the edges. Then, use the diagonal cutters or needle nose pliers to nip off a small amount at a time.


10. Follow the same steps to cut along the other dimension of the cover.

Customizing the Tank Cover

Once you have the cover cut to size, you will likely need to add cutouts for air lines, heater cables and filters. Here are a few ideas to consider.

• An easy way to add access for airlines and cords of submersible heaters and powerheads is to simply cut the corner of the cover leaving about one-half inch open to the water below. Simply score a corner and bend to snap.



• For outside filters, carefully measure from the edge of the tank to the furthest protruding edge of the filter. Transfer these measurements to the tank cover and score the outline of the cutout. Flex the cuts leading from the edge of the cover in first. Next, flex the cuts parallel to the edge and break out the piece.



• If you need a round hole or part of one, you can use a hole saw and an electric drill to cut it out. I’ve found that a 2-1/8" hole (a standard size for installing locksets) is ideal for feeding and it’s just big enough to accept the valve end of a Python water changer. When drilling, it’s best to drill from the bumpy side of the material with a piece of wood underneath. Start slowly and don’t press to hard or the material may crack. □