(I'm only in the process of building my first sump/fw
Here are instructions that helped me: [link]http://reefcentral.com/forums/showthread.php?s=&threadid=445481[/link]. I encourage you to read the entire thread, as a lot of people think this is a bad idea. I only used a 7134 bit when drilling mine
. If you do not want to drill, there are many diy
overflow designs in the archive.
Unless you only want to hide your equipment, consider using a sump larger than 5.5g, since you'll probably only add ~3-4g of usable water volume to your 20g tank. How about a rebermaid container sump (ie: 20g or 33g trashcan, 12g rubermaid container) into the 5g as a LR
/algae/plant fuge? You could use your current canister anywhere you want (main tank, sump, fuge) since its all the same water. Or you could use the cannister as a redundant filter to the main tank - you pull the return pump's power, instant qt
tank in the 5g and the main tank only loses sump's water volume. Just a thought.