Well, it is settled, eheim isn't getting any more of my money. I would never have thought of this, thanks for the post.
How tight is that seal though? Jagged, have u ever had any problems with leaks over time with these setups?
I remembered buying my air tight seal container at Wal Mart, They have different sizes incase you want to throw in a strong powerhead. Except mines were the thin tall version. The dimensions were something along the line of 5''LX15''Hx5''W. I used a Mini Rio powerhead, which was mount on the flat lid underside with the tip of the powerhead facing outside ontop. I used a series of automotive glue that once harden turns into hard plastic. I also cut the power cord and drilled a hole on the lid for it to came through. I then solder the connection up and glued around that hole also. From there on out, it was just the matter of hooking up your inlet and outlet hose to the tank and plugging it in.
The air lock tight container I used looks like this exactly. Crappy illustration but that's how mines was hooked up.
There were no leaks at all throughout the whole time I"ve used it. Easy to clean too, I recommend using tall containers so you have more media level to use(This is also determined by your output of how strong your powerhead can push water known as GPH). I had it running on a 5gallon tank and two 2.5gallon tank.
The canister I used back then worked out great, because at that time no other company was selling their nano canisters yet like the ones you see at drsfostersmith.com.
So It worked great, Would I make one again? Not really, since now they have mini canister filters out, I rather just buy one.
The only leakage point I could imagine it coming from, is on 3 places when making one of these DIY Canister Filter.
If you go cheap(Different types of Glue) and become clumsy(Over use of glue or under use) on the glueing of the 3 holes you drill out, that will only be your leakage point. The Air Tight Lock and Lock Lid, will not leak at all.
These DIY Canister Filters are all over the web back then and is now. Tons of information on them.