If you're not going to be using your Live Rock as your filtration I'd go with the canister filter. Many use the Live Rock because it is natural and less maintenance. I use both, but I'm just chicken.
Undergravel filters are a bit dated in the hobby but some still use them and admit to it openly. =)
Personally I'd not get the Rio pump. For my 55 I have MJ1200s right now but I'm getting ready to upgrade to Koralia #3s or #4s. They are a new midline powerhead and are getting raves.
Yes, you could add live rock to an established tank. I'd do it a little at a time though, not 50#s all in one shot or you'll get a big cycle again. You might consider mixing base rock with live rock to save money. The base rock will eventually become live if you surround it with live rock. A good ratio that is often suggested is 60% live to 40% base although some stretch it even further than that with the knowledge it will take longer for the live rock to seed the base.
You might want to take a look at a post I made after I answered your's last night. It has a few bits of information that might help. Mainly though keep doing what you're doing and that is asking for opinions BEFORE buying.
http://www.aquariacentral.com/forums/showthread.php?t=118995
Undergravel filters are a bit dated in the hobby but some still use them and admit to it openly. =)
Personally I'd not get the Rio pump. For my 55 I have MJ1200s right now but I'm getting ready to upgrade to Koralia #3s or #4s. They are a new midline powerhead and are getting raves.
Yes, you could add live rock to an established tank. I'd do it a little at a time though, not 50#s all in one shot or you'll get a big cycle again. You might consider mixing base rock with live rock to save money. The base rock will eventually become live if you surround it with live rock. A good ratio that is often suggested is 60% live to 40% base although some stretch it even further than that with the knowledge it will take longer for the live rock to seed the base.
You might want to take a look at a post I made after I answered your's last night. It has a few bits of information that might help. Mainly though keep doing what you're doing and that is asking for opinions BEFORE buying.
http://www.aquariacentral.com/forums/showthread.php?t=118995