The Aqua One Aquis 500 is a canister filter designed for a 100 litre aquarium. This filter is currently running on my 175 litre aquarium. Before purchasing this filter, I had done a lot of research in order to find the most suitable filter. From previous experience with canister filters I knew that I wanted a filter with low flow rate. In practice, this meant that I would have to purchase a filter designed for an aquarium smaller than the one I intended to use the filter on. This may surprise some people, however, considering the tank was heavily planted and lightly stocked, I was not concerned about the size of the filter.
The Aquis 500 was bought to replace an old Fluval canister filter. After purchasing the filter, there were several features which impressed me. The clips on each of the four corners of the filter were a welcome sight. The clips allowed the motor compartment to be easily removed and replaced, unlike the original filter which was a pain to open. This feature made maintenance and cleaning a lot easier.
The interior design of the filter was also very sleek and efficient. There was ample space for filter media and the filter was compartmentalised in an effective way, which also made it easy to clean. The filter has two baskets which hold filter media and a third compartment below the second basket where the biological media is positioned. Even with all the media that the filter came with, there was still space for more.
The attachment points for the in-going and out-going hoses were also well thought out. The attachment points were able to swivel giving the filter versatility and a great deal of practicality. Each of the attachment points has a lever which allows you to open and close the inlet/outlet pipes. This makes cleaning the filter easy, as you do not have to remove the hoses from the tank. Switch the lever, ensure the pipes are empty and detach the filter. Simple.
On the topic of pipes; the one thing that I did NOT like about this filter was the fact that at the end of each hose was a solid plastic pipe, which was U-shaped, that fitted over the edge of the aquarium. This absolutely ruined the filters otherwise sleek design. The suction cups which were supposed to attach these pipes to the glass of the aquarium were also less-than-extraordinary. The suctions cups frequently detached themselves from the glass, causing the plastic pipes to hang in the tank at a 45 degree angle.
The inlet of the filter was also a concern. The strainer on the end of the inlet pipe had large grooves in it. This resulted in several of the smaller fish getting into the filter. Being designed for a smaller aquarium, it would have made sense to make the grooves in the strainer smaller in order to avoid this problem. However, none of the fish were killed thanks to another design feature of the filter. The baskets on the inside of the filter have hole in them to one side with a pipe running through it. These line up with the inlet of the filter so that the water flows straight through to the bottom of the filter and is then pulled through the filter media from the bottom. This meant that the fish were left trapped in the lower compartment but remained unharmed.
However, it was this design feature which was also the biggest flaw in the filter. The pipe running through the filter baskets meant that the water passed through the biological media before it passed through the mechanical or chemical filtration. This is not ideal, as the biological media’s efficiency will be reduced if the media becomes clogged with debris. Most filters place the mechanical media before the biological or chemical media in order to avoid this problem. It is my personal opinion that this design feature was the cause of the problems I experienced with this filter.
While this filter was running on the 175 litre aquarium, the aquarium experienced frequent and long-lasting ammonia levels, despite a high plant mass and limited fish load. This made absolutely no-sense, considering the aquarium had been running for almost 6 months prior to putting this filter on the aquarium. After considering all possible conceivable reasons for these problems, I concluded that it was the fault of the filter.
This filter has many positive aspects and several design features which separate it from other filters on the market. However, the flaws in this filter drastically reduce its appeal. For those considering purchasing an Aqua One canister filter from the Aquis series I would recommend that you purchase a filter with a flow ten times the volume of the aquarium it will be used on. Overall, this a good quality filter. However, it does have its design flaws.