The canister filter is a type of aquarium filter that can be installed in canisters, hoses, or used as an external canister. Originally designed for the military to provide fresh water on the battlefield, this device has now been used by aquarium hobbyists worldwide.
A canister filter is typically composed of two sections: an upper section with mechanical and biological media, and a lower section with chemical media. The water flows from top to bottom through these sections before being returned back into the tank.
The benefits of owning a canister filter are many; it’s much easier to clean than other types of filters because you don’t have to worry about replacing any parts or spending time scrubbing out gunk every few weeks – all the stuff can be readily rinsed off and cleaned in an instant. This can really make your life easier when you go away for a few days and can’t be there to do the cleaning yourself; canister filters can last months or even years without needing replacement parts, so this is why they’re such a popular choice among many hobbyists and aquarium owners.
Canister filters can also hold more than enough filtration material – often up to five times as much compared to HOB (hang on back) filters. They can also provide better filtration because they can be arranged so that the water passes through each media section in descending order so that the dirtiest water can be filtered out in the bottom section.
Finally, canister filters can also produce a much higher flow rate. If you have a powerful canister filter, it can pump up to ten times more water than a HOB filter can – or even more if your canister filter has multiple output points! This means that when you are cleaning off the media in your canister filter, you don’t have to worry about taking too long and leaving your fish without enough oxygen to breathe.
The only downside of canister filters is that they’re often quite expensive for hobbyists who’re just starting out with their aquariums – but this guide will show you how to make one yourself without spending too much!
Materials you’ll need:
canister filter canister (available from Ace Hardware)
spray paint (optional)
For the canister pictured above, I have already prepared a solution of 50% water and 50% bleach. The canister can be placed in this for about ten minutes before being washed thoroughly with clean water and allowed to dry completely. Some people prefer not to use a bleach solution, so it’s up to you whether or not you want your canister painted – but know that if you do decide to just give your canister a quick scrub, it will likely come out looking duller than when you first bought it. This is because many manufacturers apply an anti-rust coating on top of the canister, and this can be taken off when you scrub too vigorously. It can still be used as an aquarium canister filter without being painted, but to restore it to its original luster and prevent rusting, you should paint your canister with a high-quality can of spray paint for metal (no cheap dollar store stuff!). This step is completely optional and entirely up to you!
Cut out three holes about one inch in diameter near the bottom end of the canister – it doesn’t matter where exactly, just make sure they’re not too close together or far apart from each other. These will serve as places where water can flow into your canister filter. To cut the holes, I used a can opener, but you can also use a drill if you wish.
Place the canister on your work surface and cut off any lip at the top using your can opener (or the drill). The canister body should come off easily when pulled against with some force. You can discard this piece or keep it to make another canister filter in the future! If you plan on making two canisters that will be placed right next to each other, make sure they fit together nicely and snugly by sanding down the edges of one of them until they do (make sure that both canisters still have their holes intact!). Another option is to stack one canister upside-down on top of the other canister, secure them together with duct tape, and cut off the canister’s lip to make them fit.
Attach the canister filter canister you’ve just made to your aquarium using three pieces of PVC piping (I used 1/2 inch diameter piping). Use a hacksaw or miter saw to trim down your lengths of piping so that they’re all relatively the same size – it doesn’t have to be perfect because you’ll soon seal everything up with silicone. You can also mix and match different sizes if you wish, but keep in mind that the larger the diameter of your tubing is, the harder it will be for water to flow through your canister filter! One length connects directly to one hole at the bottom of the canister filter canister, another length to one hole at an intermediate point on the canister filter canister, and a final piece of piping to the third hole.
Apply generous amounts of silicone sealant (aquarium safe) around the base of each PVC pipe, then press them into place inside your canister filter canister (make sure you don’t accidentally push it all the way into the canister). You should be left with three sealed tubes that are firmly attached to your canister filter canister – these will act as your intake/exhaust points for water! The silicone may dry quite quickly so it’s best not to go overboard with this step like I did, or else you might make a canister filter canister that can’t be taken apart again! Perhaps put a book on top to add some weight while the silicone cures.
Place your canister filter canister inside of your used plastic bottle and seal its top into place using duct tape or another strong adhesive, then cut off any excess parts of the bottle if necessary so that it fits snugly inside. You can leave this step out if you want, but I found it helped keep everything nice and clean since the media chamber was separate from the main canister body.
You can also make two canisters and stack them together to make a double-decker canister filter (like Bubbles’s Builds’ DIY Canister Filter 2.0! – or keep it a single canister and add more canister filter canisters on the outside to make a custom canister filter of any size!
Take your media sleeves (mine are Socks for AquaTech 10″ canisters – http://amzn.to/1QXR4aq) and cut them down the middle lengthwise, then attach one half into each end of your canister with two pieces of duct tape. You can also glue them in place if you wish, but I found that the lengths of tubing at either end kept everything nice and snug. This is important because these act as your canister filter canister’s media chambers!
Add some canister filter canister media (I used AquaTech ceramic rings and poly-filters) into each of your canister filter canisters, then place the canister filter canister that you made in Step 3 onto one end of your spray bar (or canister filter canister) and connect it to your canister filter canister using some more PVC piping (you can mix and match the size of the piping here if necessary).
At this point, you can either plug in your canister filter canisters to start them up or leave everything unplugged until you’ve filled up your canister filter canisters with water and your canister filter canister media of choice.
If you’re happy with how it looks, then congratulations – you’ve just made a canister filter canister! If you’d like to use this as a canister filter vs. HOB canisters, great – go for it!