DIY 5G. waterbottle Biofilter

[Dale]

Here's a DIY biofilter that has no moving parts and uses no energy. It operates on the "syphon effect".

This is just a brief overview. To see how I did some of the construction such as cutting the top and installing bulkheads, refer to my other 5G. project here: http://www.canreef.com/vbulletin/showthread.php?t=28197

First, I took a 5G. waterbottle and cut the top off. Then I installed one bulkhead and resealed the top.
Here's a pic so far:



I then pushed 1/2" PVC into the plastic cap that comes with the water bottle.



I then built this contraption.



This 1/2" PVC line runs from the bottle to the display and has a tee joint with a cap above the bottle so that I can prime the system (I later found I did not need this as the filter will self prime if the bottle is filled initially).
Here is a shot of the end that sits in the water.



Here's a shot of the bottom plumbing. Basically it is just 1/2" PVC that runs from the bulkhead to the sump with a tee valve in line.



How it works:

Close the tee valve.
Fill the bottle with bioballs (or any other biomedia) and add water to the system till the bottle is full.
Snap the cap in place.
Open tee valve.
Congratulations! You now have a perpetual motion biofilter.
If you get some air in the bottle you can burp the lid a little to get rid of it. You should only have to do this once though.

There are some things to consider.
First, Your sump return pump must be returning enough water to the display to compensate for the amount being syphoned off. This isn't really much of a problem as the tee valve can adjust the flow rate of the biofilter.
Second, only sink the end of the syphon feedline (the part that goes in the display tank) about an inch or two below the waterline. Also ensure that your sump can hold that much water in the event that the sump return pump fails. In my case the biofilter would continue to syphon about 15G.'s before running dry and breaking syphon.

That's it!

Here's a sideways video: