Here’s an idea for an alternative way to set up your Fluval Spec aquarium: go topless! That is to say, sans lid . . .
Going without a top is a great debate among serious aquarists, both for marine and freshwater planted tanks. There are some compelling reasons to leave that acrylic lid off your aquarium and some reasons you might want to leave it on.
Advantages and Disadvantages of a Topless Aquarium:
The big reason that people want to run their aquarium topless is the aesthetics. It gives an incredible feeling of oneness with the creatures inside the aquarium. Without a lid, you have a whole new dimension of viewing by being able to look down from above. In a planted tank, I think the view from above is gorgeous. I also love seeing the ripples from water movement at the surface.
Here are some other positive aspects of setting up an aquarium without a top:
- Aesthetics: Topless aquariums offer a clean look, with unhindered views from above and no distracting elements above the rim.
- Better Light Performance: Even clean glass can significantly block light from entering your tank. Dirty glass or frosted plastic (as is the case for the Fluval Spec lid) significantly reduces light efficiency. In the Spec, you do have the open area directly under the light, but you get better light performance at the edges of the tank if there is no lid.
- Better Gas Exchange: Having a closed-in aquarium with a lid hampers the exchange of gasses (Oxygen and/or CO2 depending on the day or night phase of plants). Without a top, the water surface area is fully exposed, and gas exchange is more uninhibited. However, with the hole in the Stock Spec top, this is not much of a difference.
- Easier Access: When feeding your fish, you don’t have to work around the light to get to your aquarium. Freely drop in the food anywhere you wish. If you have a planted tank, you can easily get your hands in quickly to trim and move plants about without messing around with moving and storing the top.
- Simplifies Maintenance: It’s not a big deal, but that lid is one more thing to clean. No cover; nothing to clean!
- Runs Cooler: With a greater surface area for air to freely flow over, the aquarium will operate slightly cooler due to evaporation. If you run a cooling fan, it will work more efficiently with the top off for easy airflow over the water surface.
- Attractive for the Spec: The Fluval Spec (and EVO) line of aquariums are rimless, with a nice clean edge of beveled glass at the top. This look is similar to the ADA rimless tanks, and it looks very nice without a top. The stock light, being attached to the end of the aquarium and not the lid, works the same with or without the top.
There are some very real arguments against operating an aquarium topless. Here are a few to consider:
- Jumpers: Some breeds of fish are known to jump. Even ones that are not known jumpers may one day decide they want to fly. With no lid, they can careen out of the aquarium. That fish is a goner unless you see it happen and can intervene.
- Curious Critters: A close cousin to jumpers, some critters like to crawl out of a lid-less aquarium. Nerite snails and Amano Shrimp are known to go for adventures outside the aquarium. We had this experience while operating without a top for a nerite snail who escaped and fell off our counter. Poor lil’ fellah. Godspeed, Tiger. . .
- Increased Evaporation: The phenomenon that makes the tank cooler, evaporation also causes water loss quicker without a top. Depending on your maintenance schedule and the conditions inside and outside your aquarium, this may or may not be a big deal. If you live in a very dry environment, the tank may experience a rapid drop in water level. This will require top-offs often, but even if you can stay abreast of the water level, adding tap water to top-off may increase the hardness of the water in your aquarium. Increasing water hardness will not be remedied until a partial water change is administered. This rise and fall of water hardness may affect the health of your fish and inverts.
- Exposure to Contaminants: With a lid, you have a bit of protection from stuff getting into your tank. If you run your aquarium topless, your water is open to the environment. This means that unintended things can be dropped into the tank. It also gives an unimpeded path for chemicals to enter from above. If care isn’t taken, dispersal of cleaning supplies or other chemicals in the area of your aquarium will have an easier time entering the water column of a topless tank.
- Risk of Equipment Falling in: This might be a long shot, but it is more plausible that a light fixture or other equipment over the tank will fall directly into the water if you don’t have a lid.
- Wintertime Heating: What is a positive in the summer becomes a negative in the winter. The additional water surface exposed will allow more heat loss in the winter and will increase the load on your tank’s heaters.
The negatives are not to be ignored. I can deal with most of the disadvantages of operating an aquarium without a lid, but the biggest downfall that keeps me from running the tank topless is the risk of fish jumping out. I don’t know the current inhabitant’s propensity for flight, but I don’t necessarily want to test them.
For owners of a Fluval Spec aquarium, the lid is easily removed and stored for a time. You can choose to display your aquarium topless for periods of time to try it out and can always revert to the top on. I certainly enjoy times when I have the lid left off; I love the look and enjoy seeing the animals and plants from a new and beautiful perspective.