Building a canister filter for a 7.5 gallon tank

So I've decided I wanted a canister filter for a 7.5 gallon tank. Well they don't make them that small. But huge thanks to YellowGuppy for introducing me to the idea of making my own! This filter was supposed to be for a future tank after Christmas. But I got way to excited and I've started the build now. I had a few hiccups in my design and decided to try new things. So I'll post the picture of my progress so far. Not a whole lot but it lead me to ask a question regarding the flow of the water running through the filter.

In the pictures you can see my inlet tube. Water will enter through the bottom, and a pump will be pulling water out of the top and back into the tank. So my question, should I extend the inlet tube so it reaches the other side of the filter, and maybe cut a bunch of small holes in it to make the water distribute evenly around the filter? This thing will be completely filled with water at all times with the water moving through it from the bottom to the top. So I don't know if it's necessary to worry about the water being evenly distributed or not. I'm no water flow expert or anything lol! I hope I haven't bored any of you. I messed up the lid so I order another container. I will have this thing finished probably by the end of the week!

 

Based on your pictures, closest design of a canister filter would be the Sunsun HW-602B. You can google images of it and get a shot of what the inside looks like inside which may help. They keep the bottom as an open water chamber supported with a "roof" that then holds your grades of sponge - coarse to fine.

You may want to consider a bleed off valve in the top of your lid as well, something to let the air out as well as some sort of pump/primer to start the siphon. There are little hand squeeze pumps you could put inline that might do the trick.

 

Based on your pictures, closest design of a canister filter would be the Sunsun HW-602B. You can google images of it and get a shot of what the inside looks like inside which may help. They keep the bottom as an open water chamber supported with a "roof" that then holds your grades of sponge - coarse to fine.

You may want to consider a bleed off valve in the top of your lid as well, something to let the air out as well as some sort of pump/primer to start the siphon. There are little hand squeeze pumps you could put inline that might do the trick.

Awesome man I'll look up that model for sure! What happens if you don't let any air out? I've never used a canister filter before so I'm just winging it here lol! I did steal the idea from a video though. But I'm making it kind of my own way. The pump I'm using will actually be sitting inside the canister at the top near the lid. So I will have it full of water before I turn it on. And then it should just start sucking water without the need to prime right?
SotaAquatics is that canister any good? The sun sun one. Its scary how close mine is to that one, and it's only $60... The only difference really is mine is flowing in reverse and my pump is at the top on the inside. Other than that it's the same thing! I am having fun building this thing, But I really hope it works as good or better than the sun sun canister xD but it looks like they don't really worry about the water flowing "evenly" throughout the canister, just a grid to hold the filter media. Easy enough!

 

I've heard of people throwing an airstone in their DIY canisters to help keep the flow random, which makes it more likely that you'll end up "using" all of your filter media, rather than water just channeling through one path of least resistance and essentially ignoring media that's less accessible. Then again, you've now made more canister filters than I have, so I'm not too sure!

 

I've heard of people throwing an airstone in their DIY canisters to help keep the flow random, which makes it more likely that you'll end up "using" all of your filter media, rather than water just channeling through one path of least resistance and essentially ignoring media that's less accessible. Then again, you've now made more canister filters than I have, so I'm not too sure!

Yea I was wondering if that would end up happening, but whos to say for sure! The nice thing about this build is I can always upgrade or go back in change things as I see fit! I think the best thing now is to finish the build and give it a test run and see how the water flows!

Do you know if it's a good idea to run this filter on my existing tank to get it cycled? Or is that a way to bring potential diseases to a new tank?

 

Update on my progress. Got my new container today and got the pump installed In the lid! Just waiting for my media base to dry. I used the bottom of my 1st container to make a base to hold the media above the Inlet tube. The rubber grommets I used for the inlet and outlet are no Joke! Gotta heat the heck out of the tubes to get them to go in the grommets. And the tubes aren't budging! No silicone needed.

Accept the hole I made for the air pump wire to come out, it's not super tight. I'm wondering if I should seal this hole with silicone? It won't leak because it's coming out of the lid. But I'm not sure if the canister is supposed to be air tight or not

 

Looks good! I think you may want to silicone by that pump wire just incase. I haven't made a cannister filter myself but have made some CO2 reactors before - basically same idea as far as pumping water through another container like this. I did not silicone around one of my input hoses and I had water shooting out.

 

Looks good! I think you may want to silicone by that pump wire just incase. I haven't made a cannister filter myself but have made some CO2 reactors before - basically same idea as far as pumping water through another container like this. I did not silicone around one of my input hoses and I had water shooting out.

Thank you! Yes I actually decided to silicone it last night after diving a little deeper into how canister filters really work. I guess they are under pressure. I appreciate the feedback!

 

Are you making a canister filter or sump? A canister filter needs to be air tight, any leak and water will come out since it is under pressure

 

Are you making a canister filter or sump? A canister filter needs to be air tight, any leak and water will come out since it is under pressure

I'm pretty sure it's a canister lol. I don't know what a sump is tbh. Is it one of those things that sit on top of the tank and water moves from left to right through the media or something like that?

 

I'm pretty sure it's a canister lol. I don't know what a sump is tbh. Is it one of those things that sit on top of the tank and water moves from left to right through the media or something like that?

Sump is another tank used for filtration of the main tank. Sumps dont need to be airtight they rely on overflow

 

I had a minor set back. The media holder had a leg break off lol. Guess I didn't glue them very well cause I pulled them all off pretty easy. Used silicone this time instead of super glue. Could be due to the very slippery plastic I'm using. I did try and rough it up. Anyways I drilled some holes in it and I was wondering if anyone else thought I should drill more holes or not? There's no real set plan here I'm just trying my best to make it work well! You can see the holes I drilled, the water will be sucked up through those holes to come in contact with the 1st layer of media (coarse sponge) I'm wondering if I should make more holes or not , they are kind of hard to see

 

What kind of material are the legs? If they are PEX pipes then they will not stick to glue.

Id drill more holes, because once the media goes in and mulm and gunk builds up the flow will be reduced significantly. To be honest, in my canisters I dont have media holders I just dump all the media in.

 

What kind of material are the legs? If they are PEX pipes then they will not stick to glue.

Id drill more holes, because once the media goes in and mulm and gunk builds up the flow will be reduced significantly. To be honest, in my canisters I dont have media holders I just dump all the media in.

I actually can't remember the exact material probably pex tho. The silicone seemed to work ok! But yea I might just try without!

 

Finally finished the build! Still need to test it. And I wish I had more mesh bags for more biomedia. But I think the amount of filter media is overkill for a 7.5 gallon tank. Ive been working like crazy so Ill probably test it in a few days or tomorrow. Let me know what you guys think of it! Looking at it again tho I probably will fill all the empty space with biomedia. Or maybe someone could recommend a good Chem filtration or something by seachem lol. I'm a simple dude tho I'll probably stick to the classic mech and bio filtration Cherryshrimp420 you where so right about forgetting the "media holder" I built. Just use more sponge instead! Nothing but media. Love your name btw

 

That looks great, hopefully it doesnt leak.

Dont use chem filtration just sponge and rocks are all you need

 

Are you going to run a pre filter sponge on the intake? My only worry without that and the new design without the media holder is the sponge right by the intake getting clogged fairly quickly - though I can't tell how coarse the sponge is in that picture.

 

Are you going to run a pre filter sponge on the intake? My only worry without that and the new design without the media holder is the sponge right by the intake getting clogged fairly quickly - though I can't tell how coarse the sponge is in that picture.

Thanks for the insight, the media holder didn't work out anyway lol I need to come up with a different idea all together. I was just trying to use the materials I had around the house I'll definitely keep my eye on it for the 1st couple of months and see if that does happen.

I tested out the filter yesterday in the bathtub. It started off terrible lol. There must have been a kink in the tube I didn't see cause it just didn't work until I tried it again. But then I had a reverse syphon going and I didn't realize it so I turned it on for a 3rd time and it was so wonky . ANYWAYS I got it working properly , water was flowing in and out but there was a constant flow of air bubbles mixed in with the water flow, would that mean this filter isn't sealed properly? I'm thinking it's sucking air at the seams I didn't silicone.

 

Looks impressive.
(Anyways, on to purchasing another absolutely silent, 5 wattage, Eden 501 mini-canister for 25 bucks)

 

Looks impressive.
(Anyways, on to purchasing another absolutely silent, 5 wattage, Eden 501 mini-canister for 25 bucks)

you be quiet. I'll have to look that one up xD I'm in Canada and it seems to be very hard to find some of these products people recommend me
ruud this is what I deal with all the time. I know there's more than just Amazon but I already have a feeling I know what's going to happen lol