Zoo Med 501 Canister Filter Review
Pre-drilled spray bar
Intake tube with strainer
Ceramic media (biological)
Cylindrical sponge media (mechanical)
Carbon media (chemical) bag
The 501 comes packaged with some components pre-assembled and, curiously, other components unassembled. For example, the included cylindrical sponge is already inside the canister and positioned over the attached intake within the canister. Yet the very small rubber feet that fit the outside of the bottom of the canister are inside of a small sealed plastic bag. The rubber feet have to be attached, yet the sponge is already in place. The other media, ceramic (biological) and carbon (chemical) are each bagged separately. If you plan to not utilize the included carbon bag, the amount of ceramic media provided is insufficient to solely fill the bio/chemical media chamber.
The instructions are printed in both Spanish and English and include step-by-step captioned illustrations. However, before the illustrations, there are text instructions that, oddly, do not coincide with the illustrated instructions. This inconsistency can lead to confusion. Most people would expect that the numbered text would correspond with the numbered illustrations. They don't. In fact, they're basically separate instructions all together. The good news is that the components are made such that they will only fit together one way. It is nearly impossible to assemble anything backwards.
The strange logic behind having some instructions in text and some in illustrations aside, assembly is quite easy and straightforward. The filter is an oval shape, rather than round or square like most larger canisters. This offers no real advantage other than having a more contemporary appearance versus typical boxy canisters. The pump is self contained within the top of the canister, like many of its larger cousins. Access to the inside of the filter housing is achieved by removing the top portion via two "sliding" locks, one on either side of the filter. Upon removing the top of the filter, the canister housing is split into two equal size chambers with a divider separating the two. One side houses both the ceramic and carbon media, while the other side contains the cylindrical sponge. All components fit nicely together. Assembly from start to finish, including attachment of components to tank, took about 25 minutes.
The rigid plastic intake tube is 10 inches in length. Depending on the depth of the tank you intend to use this filter on and depending on how deep the substrate, you may need to cut the tube. For most tanks, this will not be necessary. The two flexible hoses are each only 20 inches in length, which reduces the placement options within the aquarium.
Priming the filter is achieved by simply filling it with water. This is easily accomplished via the removable "plug" in the top of the filter. Remove the plug, pour water in until the canister is full, then replace the plug. Like with most canisters, there is no off/on switch. Simply plug the power cord into an AC outlet and the filter will start immediately. It is quite noisy at start-up as it works to purge trapped air within the canister and hoses. It only takes a few minutes for all of the air to be forced out. Once all the air has been removed, the filter runs very quietly.
Because the 501 is designed for vivariums and smaller aquariums (< 30 gallons), it is not unexpected that the pump is not very powerful. It is actually advertised as a turtle filter. In fact, the pump is only rated at 80 gallons per hour. It is not powerful enough to place it underneath the aquarium like its larger cousins. Typically, one of the main advantages to an external canister filter is the ability to hide it within the cabinet of wooden stands or simply underneath a tank, which allows for the tank to be placed closer to the wall. The 501 has to be placed level with the tank it is filtering, which can present a challenge if you are trying to hide this filter yet keep the back of the aquarium close to a wall or some other structure.
Unlike larger canisters, this filter is not equipped with shut-off valves for disconnecting the hoses from the unit. Therefore, cleaning the filter is most easily accomplished by leaving the tubes intact and lifting the pump-head from the filter housing. The only problem with this method is remembering that any water remaining in the tubes will flow out once the pump-head is lifted.
Zoo Med claims this filter can run dry for 30 days without damaging the unit. The 501 also comes with a one year warranty.
Confusing formatted instructions
Must be level with the aquarium
No shut-off valves for hoses
Short hose lengths
If you're not concerned about the filter being visible, the 501 is a nice, quiet external canister filter for smaller aquariums. In fact, smaller external canister filters are not very common, making this new addition to the market quite attractive.