DIY : Built In Tanks
I've built a few DIY built-ins, starting with a 15g in a bar, and then a 20g in a nursery (that one got me about 20 minutes of extra sleep every morning for a while). This article documents general things to watch or plan for. The photos reference my most recent installation.
Figure 1
Replaced an existing book-case, for a 66 gallon installation.
Generally...
My top 12 points for site evaluation are:
- Tank dimensions/availability for area available
- Sunlight exposure
- Viewing angles & height
- Electrical power
- Lighting
- Feeding & tank maintenance
- Filter location and access
- Storage of food and peripheral items
- Heat control
- Humidity control
- Water supply access
- Drain access
1) Tank dimensions/availability for area available
If you need to construct a custom tank, the dimensions should still be fish-friendly. Forget about making a tank which is very tall, long and only a few inches thick. You will be disappointed in regards to how few fish it will hold, how small the fish have to be, how vulnerable it is to problems (power failure, algae, etc), and it will be very difficult to do any maintenance. Try to keep to normal dimensions. For maintenance, you have about a 24" reach.
2) Sunlight exposure
You can control many things, but where the sun rises can be a real problem. Direct sunlight promotes a rate of algae growth which can be very difficult to control. Try for indirect exposure only.
3) Viewing angles & height
Wall tanks are often large and set back. The height should correspond to the viewer's normal eye level. Measure your eye level to the ground (whether sitting or standing). Your sightline should hit the tank about 2/3 of the way up. This gives you a better view of the tank's bottom (which usually has more stuff) and less of a view of the surface (which is not so heavily decorated normally). Adjust this downwards a bit if you have kids, or plan a chair or perch which will be close by.
For the tank shown here, it was to be equally viewed standing and from a couch, so I started the tank at 36" from the floor, ending at 54" (18" high). Sightlines were 39" (sitting) and 64" (standing). This was an acceptable compromise, but working with a single sightline is better.
4) Electrical power
Typically needing between 6 and 10 watts per gallon, the ideal is to have a dedicated circuit fed through a GFI outlet. If this is not available, use a GFI outlet to plug your power bar into. In North America, GFI outlets are an economic and simple replacement to a normal outlet. They sense leaks by comparing currents, and will shut off the power in the event of a problem.
5) Lighting
A built-in allows you to have a matching canopy where almost any light level can be arranged. Commonly used, shop light fixtures for 48" fluorescent tubes are readily available and economical. A mix of different tubes will give you a wide light spectrum.
6) Feeding and tank maintenance
Feeding is done often, so don't make it impractical to do. Leave yourself a small hatch somewhere. Automatic feeders are ideal for built-in tanks. Allow about 8" between overhead lights and the edge of the tank (for your arm). Rear access is usually impossible (unless you build between rooms). The canopy of the tank shown here opens in 3 stages to accommodate feeding, semi-annual maintenance, and teardowns.
7) Filter location and access
Powerfilters are not usually practical with built-ins, so that leaves canisters, sumps and fluidized beds. All these systems have hoses, connectors and pumps, so water contact to electrical is a potential hazard, as well as protecting the interior of the cabinet from water damage. I start my cabinet design after purchasing a plastic tub or liner which the filters will sit in. It's easier to shape lumber around a plastic container, than to try the opposite.
8) Storage of food and peripheral items
Foods should be kept in a cool dry location. Inside and above a built-in, will be warm & humid, so unsuitable.
9) Heat control
Depending on your normal room ambient and the amount of ventilation, it may be difficult to vent trapped heat (from the water, filter motors, lights and ballasts). If you suspect this will be a problem, use a snug glass cover on the tank, and install your ballasts elsewhere in a vented location. There should always be some convection venting to the canopy above the tank, for fresh air to be available.
10) Humidity control
Canopy venting and a glass cover will control this. An improper seal and/or no ventilation will quickly make a mess (moulds growing inside the framing/drywall above the tank).
11) Water supply access
Ideally a pre-mixed single supply line should be brought through the wall/floor to the tank. Control valve can be at the tank (ideally) or where the cold/hot water is mixed (so small diameter low pressure hose can be used). Even a cold-water only line is very practical. This limits the amount and rate of water changes (so the tank temperature does not change excessively). The larger the tank, the less susceptible it is to small amounts of cold water.
12) Drain access
Usually requiring a steady drop, drain lines are much more difficult to have installed than supply lines. Because old tank water is usually high in TDS and nitrate rich, it makes an excellent source for house or garden plants, so consider draining it directly out to a storage barrel, or in a manner that you can use it for your indoor plants.
Installing an overflow (either along the back or through a drilled bottom) allows you to employ a slow speed automatic water change system (using only a low pressure cold water supply line). Check out automatic water sprinkler systems at your local home renovation outlet. You need one controller and a single fluid relay. Design so that your overflow cannot get clogged, and your rate of incoming water is significantly less than your overflow capacity. I currently have 54 tanks at work running on such a system, receiving 4 small water changes daily. System maintenance has been virtually nothing.
Alternately set it to trickle flow 24 hours a day. A drop of water every few seconds adds up to a lot of water change capability. A weekly 20% water change in a 100 gallon tank takes about 2 cups of water per hour.
Details...
Returning back to the illustrated installation, stand was basically a 2x4 frame using 3/4" plywood base, with 1/2 styrofoam between the base and the aquarium. The light canopy doubles as a shelf. The lights are 2 sets of shop lights and one incandescent light (transition light for sunrise/sunset, to minimize shock from main lights).
Figure 2
The front of the canopy opens on a piano hinge to provide access to the glass cover for feeding. For details on building your own glass cover, go here.
Figure 3
By inserting two triangular wedges (see canopy ends in Figure 3), the entire canopy is angled upwards, taking the front set of lights with it. This is used once or twice a year for serious maintenance.
The entire canopy can be removed. The rear set of lights are attached to the wall, and remain as service lights when doing a teardown. The tank is in a notch in the wall, so without artificial lighting, it would be difficult to see much.
Figure 4
Figure 4 shows the right side cabinet with pumps and electrical system.
Figure 5
Figure 5 shows a better detail on the wiring. Several of the utility receptacles are wired off of the delay timer in the lower box. The delay timer switches off the filters and heaters for typically 10 minutes. This is useful for feeding or for water changes. The 2nd canister filter (not seen behind the 1st filter) runs a continuous gravel vacuum, so turning it off while feeding is important. The delay timer has a single relay and normally works as a delay OFF timer, so I added an external relay to reverse the function. If you want a timer to turn devices off for a set time (instead of the reverse), look for one which has a relay with 3 outputs (NC, COMM and NO). Wire your devices across the COMM and the NC (normally closed). When the timer is enabled, the NC contact remains open (turning off anything plugged into it). For more details on building a delay timer, go here.
The continuous gravel vac is run through a very old Fluval 201 filter. During water changes, I remove water from the aquarium by running it through this filter in reverse, effectively backwashing the filter. For more details on this gravel vac or backwashing your canister filter, go here.
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