DIY Aquarium Canister Filter




Introduction: DIY Aquarium Canister Filter

About: I enjoy building things, repairing things or just working with my hands. I get bored easily so i tend to do many projects.

I've wanted to build this project for some time now. Finally had the time. I esentially made one and a half. The first filter leaked and had some design flaws. so mid way through I changed the whole design.
Disregard the threaded pipe cap and the rounded cap. those were from the original design.

You'll need:
8" of 4" diameter PVC pipe
1 - 4" diameter plug
1 - 4" diameter rubber end cap with hose clamp
2 - female garden hose repair ends
2 - 1/2" threaded valves
4 - 3/4" to 1/2" threaded plastic hose conections
1 - male garden hose threaded (2 pictured for old design)
3 - pvc grates about 1 1/2" tall
1 - 3/4' 90 degree corner tube(has hose ends)
some small hose clamps
PVC cleaner
PVC glue
teflon tape
aquarium silicon
20' - 3/4" tubing
5' - 1" tubing
3 small zip-ties
and of course a pump. mine was a 700gph in line pump

Filter media:
poly sponge(got one for car washing)
knee high stockings( cheap ones in those little plastic balls)

small drill bit
7/8" spade bit
coping saw
utility knife
flat head screw driver
channel lock pliers
cresent wrench
needle nose pliers
tape measure
sanding block

I may have forgoten a few things and you may need to swap a few parts to fit your needs exactly. I hope I explain it well enough to be understood. Any comments feel free to post. also please rate!

make the pump PULL water in the top and out the bottom. do not plumb it to push water through. it builds to much pressure and WILL blow the plug out of the top. I found that out the hard way. thank God for those valves installed or it would have syphoned my whole tank onto the floor. instead i caught it quickly and only about a gallon spilled.

Step 1: Drilling Holes

Keep in mind the drilling photo was from the old design but the process is the same.the pipe photo is the good design. From the bottom of the pipe just above the rubber end cap  drill a hole with a small bit in the center of where your male garden hose adapter will screw in. this will keep your spade bit centered. drill with your spade bit slowly so you don't throw shrapnel around your room.
you may need to smooth it out or slightly enlarge your hole with a bit like the one shown. I didnt make the hole too large. i wanted a good seal. I wrapped teflon tape around the adapter a few times then threaded it into the pipe with the cresent wrench. take your silicon and run a bead around the adapter on both the inside and the outside. i dont suggest smoothing with your finger like i attempted. its difficult to clean off your hands. let this silicon cure for the recomended 48 hours before filling the filter with water for best seal.

the filter baskets will sit just on top of the outlet tube. to keep them laying even i glued a small piece of PVC pipe opposite the outlet tube at the same height.

Step 2: Filter Baskets

These are the grates that cover floor drains. I had to cut them down to just the main diameter so they would fit in the pipe. i used a coping saw. first i made small relief cuts(shown in second photo) as it made it easier when you ran the coping saw around the outside of it. my first one didn't come out quite as nice as i hoped but the other two were better.i just kept testing to see if it fit in the pipe and trimed off an excess with a utility knife. I sanded all the burs off. also i attatched a short zip tie to the basket to make removal easier

Step 3: Valves and Hose Connections

This is the part that you may need to adapt to your situation depending on what your plumbing supply store had. I used the valves to stop the water flow when I need to change the filter media. Put teflon tape on the threaded 3/4" to 1/2" tube conector then thread them each into the valves.youll need to connect your hoses to the pump and to the valves. its very detailed as to which hoses to wear but look at the pictures. also if you should be able to figure out how you need to set it up. I used the female garden hose connectors to attatch to the filter itself. youll need to slide on the hose then use the channel lock pliers to pinch the connector down into the hose. i had to attatch the 90 degree corner to the bottom or outlet of the filter so the hose wouldnt kink. the technique i used to get the hoses to fit was use very hot almost boiling water and let the hose sit in it for 30 seconds or so then take it out and stretch it open with the needle nose pliers. then give it your all and force it onto the connectors. use a towel to help grip and protect your hands. try to get them seated as far on as possible for best fit. if needed because of a slow leak or just for more security attatch hose clamps to the ends also.

also put in hoses to and from the tank. one valve should be on each the inlet and outlet hoses. my hose from the tank happened to be 1" diameter but you'll need to get one to fit your pump.
the hose to the tank was 3/4" just to make things the same.

Step 4: Filter Media

The filter media used was a poly sponge found in the cleaning section of my hardware store. its suggested use was for cars and cleaning because it resisted solvents. it doesnt have the large holes that dish washing sponges have and holds together longer. place your filter basket on the sponge and cut around it with the utility knife. the sponge should be thick enough you can filet it and make two filters from it. make a small hole in the center so the zip tie from the basket can fit through.

the second basket contains the activated carbon. i bought some knee high panty hose from a certain super center and poured a decent amout into it. it isnt stuffed by anymeans. it maybe has a cup worth of carbon in it. loosly tie the end in a knot so you can possibly reuse it. lay it in the basket around the zip tie and rearrange the carbon so it fits nicely.

the third basket would contain the bio-balls. i didnt have any as they were in delivery but the instructions are simple. put them in the basket.

Step 5: Put It All Together

first wash or rinse the whole thing off very well. you wouldnt want to contaminate your tank with anything.
put the rubber plug on the bottom of the pipe. tighten the hose clamp. attatch the tube to the outlet valve. drop in your filter baskets remember bio balls first, then carbon sock, then sponge. push the plug into the top. tighten its screw.  screw on the inlet tube. and begin the water flow. hopefully you did everything correctly and it doesnt leak. my first design leaked around the threaded cap thats why i scrapped it.

once its running it should work like a dream. I hope this was explained clearly and detailed. it was my first instructable after all.
thanks for reading!



  • Fix It! Contest

    Fix It! Contest
  • Creative Misuse Contest

    Creative Misuse Contest
  • Water Contest

    Water Contest

24 Discussions

Hi, very good idea and info, I have a Jecod UV filter BF 9000E but it doesn't seam to be good enough, I wanted to put secondary filter, could I use the canister filter as that secondary filter, do you think it will work as the Jecod is a pressure filter. Thanks Patrick

So the biggest tip here is that the pump needs to suck from the fresh filtered side of the filter and pump up to the top? Check!

Thanks for the write up!

6 replies

Yes. This was a mistake I learned the hard way. Pushing water through causes too much resistance. I blew the filter open and spilled water everywhere.

I could see that happening! I'm really torn between building a filter or buying a cheap Chinese unit (under $50 with one pound of ceramic media, 40 bio balls, and a 265GPH pump)...the pump I have I believe is submersible only...that will be the deciding factor unfortunately. I've bookmarked this for future use though...much appreciated!

I was wondering if you bought the cheap Chinese model and if you still had the link to it.

Greatly appreciate it if you do!



A link from my Amazon order history...!

By way...the instructions will make you laugh. That said, once you have it set, and everything in the right order and flowing in the right direction, its a BEAST of a filter.

Hey thanks! I bought a Chinese four-wheeler a few years ago for my kids and I still chuckle when I read stuff in the manual like "Ride careful and have a flowery day"

Thanks for getting back to me so fast as well. :)

I picked mine up at Ace hardware.

That's a link to one, or google 4"rubber end cap. Some go as low as $3.75

thank you for fast response, what i meant is the other end piece, the one with the red piece and an output. thank you again

Oh it is a 4" mechanical test plug.

Also found at Ace hardware in the store but here is a version online.

Oh it is a 4" mechanical test plug.

Also found at Ace hardware in the store but here is a version online.

Oh it is a 4" mechanical test plug.

Also found at Ace hardware in the store but here is a version online.

All in all I like your design ,its really simple which is good.Some people get way overboard with they're life support creations and rely way too much on technology instead of basic biology.For those who don't know much about keeping fish,remember this one rule.The bigger the tank the more stable the system will be especially in a situation when you lose power often. Where I live we have too many power outages,so I have to keep that in mind when creating anything for life support which is one of the reasons I haven't got back into a marine setup since I moved here.In a marine system water chemistry ,temp,etc are critical.If you lose power or the ability to keep the water chemistry stable you can have a massive die off happen rapidly especially in smaller systems.As to your system -out of curiosity how was the flow through using the poly sponge vs.regular filter media ? I tried using something similar on a hanging filter one time and found that it clogged very quickly because its pretty much designed to hold water rather than let it flow through like say acrylic stuffing or filter wool etc.I designed something close to what you have there and used a bunch of net bags that you get when you buy things like onions or garlic.They're chemically inert, have tons of surface area for bacteria to grow and tend to catch the larger debris without clogging.I usually use the netting 1st, then a layer of landscaping gravel like the stuff you see in playgrounds mixed with a couple of tablespoons of carbon,then bio balls last.Anyways thumbs up on your creation.

1 reply

Thank you for the comment, sorry its taken 8 months to reply. yes the sponge was a bit of an issue. it did hold to much water. but it did collect ALOT of bio matter. I had to remove and clean it every 3 days or so.