Another crazy idea...would this work?

Discussion in 'DIY - Do It Yourself' started by JustMe, Apr 10, 2010.

  1. JustMe

    JustMeNew MemberMember

    I was cleaning out my tank when the idea came to me of making a homemade canister filter. I thought of some simple ideas to construct it, and I wanna run them by you guys for insight.

    Here's a simplified version of how I'm building it:

    Get a 2 liter bottle and drill 2 holes on the side, near the bottom
    Drill 1 hole in the middle of the cap, cap the bottle
    Put tubing in all 3 holes
    Seal all holes to make them airtight
    Fill bottle with filter media

    Here's how it works:

    Dirty water will siphon from the tank into an intake tube, which will run below the tank into one of the two holes near the bottom of the bottle. The dirty water will run upwards through the 2 liter towards the cap, being filtered by mechanical, chemical, and biological media through its course. The other hole near the bottom has tubing connected to a powerful air pump, which will produce bubbles that flow towards the cap. As the water passes through the media, it will hit the cap, which will have a single hole with tubing. The bubbles from the air pump will push the water through the hole in the cap, which is connected to tubing that relays the filtered water back into the tank.

    My only concern is the bubbles. Will the bubbles actually PUSH the water through the tubing with enough lift back into the tank? I know I can use a pump or powerhead, but I'm wondering if bubbles will provide enough lift. The whole system is airtight, so the only way for the oxygen to escape is through the cap, which should push the water along with it. I'm unsure if it will actually work- will the bubbles carry the water or not?

    Tell me what you guys think before I build it.
  2. bass master

    bass masterWell Known MemberMember

    I personally doubt it would, I just see the air going up the return tube without any water with it
  3. Fish_Man

    Fish_ManValued MemberMember

    Sounds like an interesting plan but I can't be the one to help you with any flaws that might occur.

    You can always youtube the DIY canister. I've seem a lot of videos on them, that could help you?
  4. Aquarist

    AquaristFishlore LegendMember

    Hello JustMe,

    I've moved your thread to General Discussions/DIY - Do It Yourself section of the forum to help you to receive more responses.
  5. ilikefish

    ilikefishValued MemberMember

    sounds like some testing is needed... To the lab!... jk... but IMO if you put the tubing that comes out of the cap a bit down into the filter media I don't know why this wouldn't work... it would be a bit slow though... if I were going to do this I would use a larger hose (like a small water vacum's hose to make it flow faster... but I like the ingenuity : )
  6. bass master

    bass masterWell Known MemberMember

    sorry if I always sound like a complete critic... but I think the even if the hose goes all the way down to the bottom of the canister, and if the air pump is enough to force the water out back into the tube, eventually the bottle would just fill up with air all the way down to the bottom of the hose and then air would just continue to go through the tube without water. Maybe Im wrong though, Id be interested to see how things go, good luck!
  7. ilikefish

    ilikefishValued MemberMember

    No offense man but I know for sure this is wrong... Air would have a heck of a time pushing water out of a 2 litter bottle... Air would rather just escape itself.. once it reaches the exhaust hose it would simply escape till the water covered the exhaust hose then push the water down a bit and repeat... and I'm not 100% sure but I would imagine that the air would take a bit of water with it every-time this happened...
    Last edited by a moderator: Apr 13, 2010
  8. OP

    JustMeNew MemberMember

    @ilikefish: Thanks for the tip, I was thinking of using 1/2 inch diameter vinyl tubing for the return tube. The problem is that if the tubing diameter is too large, it's easier for the air to escape without pushing the water. I'm still deciding between 1/2 inch and 1/4 inch, I'm gonna probably test both.

    @bassmaster2010: Thanks for the input. It's better to hear from both sides of the argument so I can see potential flaws. I'm gonna start building on Wednesday, I'll let you know how it goes.

    Do you guys think it would be beneficial to make the intake tube larger in diamater than the return tube? Since the water is siphoning down, below the tank, water will rush down much faster than water being returned to the tank. I'm thinking the water coming in may give the water coming out a little "push."

    The entire bottle will be below the water level in the tank, so when the water siphons for the first time, it'll go down the intake tube, fill up the bottle entirely, and fill up the return tube to match the water level in the tank. So there would already be water loaded into the return tube, I just need the air to push the water over the edge of the tank and it'll work. After the air pump is turned on, the bubbles will either:

    1. Push the water in the return tube over the "hill" and into the tank.


    2. Go straight through the residing water in the return tube and exit without giving any push.

    I think if I use a tube small enough in diamater, such as 1/4 inch, the bubbles will be forced to push the water through the return tube due to a lack of escape room- air going around the water.

    I'm also wondering if adding more air pumps would increase the water flow (more gph), or if it would just be too much air flowing through the tube and limiting water flow.

    I like the small debate going on, it gives insight into both sides of the argument. I'm gonna start building on Wednesday- it'll be done by the weekend. I'll let everyone know how it goes. :)
    Last edited: Apr 13, 2010
  9. ilikefish

    ilikefishValued MemberMember

    Exactly... The surface tension and adhesion of the water will cause it to "grab" the plastic of the hose and the air can push the water or push the water... Try it and let us know! : )