Canister filters are a very effective and popular method of filtration for freshwater aquariums.  For marine reef aquariums, a canister filter can pose a few problems because the tendency to quickly clog up with debris and constantly produce nitrates.  We thought it would be great to show you guys that Canister filters still have some wonderful applications for your reef tank outside of being the main filtration method.

A canister filter actively forces all of the water entering the canister to pass through the media with no chance of the water channeling around the media which means they are extremely effective at getting your water in contact with filter media.

Filter 1

The beauty of a canister filter is that you can employ chemical, biological, and mechanical filtration all in one compact space and you have the freedom to utilize any combination of media inside the filter.   You are also not limited to a specific brand or type, most canisters filters will work with just about any filter media on the market.

A very clever use for a canister filter is when moving your tank or setting up a new tank or quarantine tank.  Fill your canister filter with biological filter media such as ceramic rings or bio-balls and then run the canister filter on your existing tank 4-6 weeks prior to moving or setting up a separate tank.  The biological filtration inside the canister will establish during this time. The canister filter can then be transferred to the new tank to help quickly get the tank through a cycle and reduce any risk of exposing your fish to deadly ammonia during the transfer.

filter 2

If you are setting up a quarantine or holding tank, a canister filter is perfectly suitable to be the primary source of filtration since the levels of debris will likely be far less compared to a display reef tank full of rock, fish and corals. In this case, I would choose to run both mechanical filter sponges and biological filter media.  Then add some carbon on an as needed basis to remove medications or just keep the water in pristine condition.

Canister filters also work great as a sort of deep cleaning tool.  Just like the pool monster that runs around the bottom of your swimming pool catching leaves, the canister filter can be used to catch and remove debris from your aquarium water.  Turn off your filtration, break out the elbow grease and scrape your glass, blow off the rocks and even stir up the sand bed in very small portions.  This will get all kinds of debris and detritus suspended into the water column.  Just be careful with your sand bed because deep sand beds over 2” deep should not be disturbed but if you are like me and prefer to keep very shallow bed of sand, stirring up small areas on a regular basis is a great way to keep the tank clean.

filter 3

Next, fill your canister with some coarse plastic sponges along with some fine filter floss or micron pads.  Then just take the canister filter and move it around the tank to pull out this suspended debris without having to perform a water change.  The long uptake tube of the canister filter makes it easy to reach down to deeper depths that would otherwise may not be effectively filtered by your primary filtration.  The water is filtered by the canister and simply recycled back into your display.  Just as long as you are careful not to allow sand or rocks to enter the filter, this is a great way to get detritus out of your tank on a regular basis which will result in a cleaner, more healthy aquarium.

The same concept could apply for polishing your water as well. Fill the canister full of carbon and some fine filter floss and just run it for 24 hours.  The carbon will help remove colors and odors from the water and the fine filter floss will catch small particles.  The end result will be ultra clear water for a beautiful viewing experience. Remove it from your tank and show off your hard work to your family and friends.

Canister filters, although messy and slightly problematic on a reef tank, can stills serve many purposes.