How much bio filtration is needed?

What type of bio filtration are you referring to? Rock and sand--not that I've heard of, no. Power filters and such--yes, because many of these do not provide areas for anaerobic bacteria populations, and contribute to high nitrate levels, although they are very efficient at dealing with ammonia and nitrite.

What do you want in the tank? 1.5-2 pounds of live rock, and about 3 inches of sand, should be ample, especially in a reef. With larger, predatory fish, where cleaners are tough to keep,some mechanical filtration is beneficial, but rock and sand will still supply ample biological filtration capacity.

Power filters aren't really needed in SW setups for biological filtration, and can be a lot of trouble (IMO) since they require constant maintenance to remain functional. They are good for the mechanical filtration in a predator tank, but will require more work on your part.

Rock and Sand. I do not use any power filters on my SW setups for biological filtration. All filters rely on some sort of media, and solid wastes are easily trapped in this media. Once trapped there, it's out of reach of the normal cleaners in a tank, like snails, shrimp, crabs, worms, and stars. Unless you diligently clean the media, this means that the solid waste decomposes in the media, adding more ammonia. If it's not trapped, the cleaners get it and make the tank cleaner. I use powerheads for water movement, but no power filters at all. The rock and sand are ample biological filtration in conjunction with a cleaner crew for all but an overstocked tank.

Others do use power filters, but since I don't use them, I can't recommend one. Sorry.

I was told to use about 1lb of live rock for every gallon of water and use the live sand. They didn't say how much though. I guess I 'm a little nervous on the filtration. I cannot use the wet/dry system, I need to use ones that hang or the canister ones. What would you recomend for the flitration?

Just to clarify, in case the confusion is based on phrasing:

A complete biological filtration system is:

- 3" or deeper sand bed in your tank. It should be seeded with at least 10% live sand. (Preferably not the stuff sold in bags at a LFS [Live Fish Seller].) Deeper than 3" is beneficial if you have many creatures that shift the sand a lot. (Many people go for 4".)

- A minimum of 1 lb of live rock per gallon. 1.5 to 2 lbs per gallon is safer.

- Snails, hermit crabs, other crabs and shrimp, serpent/brittle stars, and sea cucumbers (in approximate order of desireability) can clean up the excess food and finish off your biological filtration. Your livesand and liverock should also come with life that cleans the tank or at least reduces ammonia, nitrites, and nitrates. This is referred to as a cleanup crew.

That's it.

The only time to replace one of those three elements with an artificial (hang on or cannister) system is if you are keeping an animal that will kill the cleaning crew or otherwise destroy one of the three elements above.

Mechanical pieces to this filtration model include:
- Either a protien skimmer (more popular) or an Emperor 400 per 3' of tank width (recommended by Ray Pollett).
- No matter what, you want enough powerheads to cycle every gallon of water at least 8 times per hour.

Many LFS are years to decades behind the times... They are also in business to make money, so they want to sell you the option that makes them the most money, all other things being equal.

If I'm adding 10%l live sand, then what other type sand can be used?
Playbox sand from your hardware store. Read the sticky thread at the top of the forum to get more info about sand and how to cycle a tank:
http://www.aquariacentral.com/forums/showthread.php?s=&threadid=11232

Now these power head, could that be something like a magnum 350?
Yep. If you have a cannister already, you can take all of the media out of it and use it as an expensive powerhead. A maxijet powerhead can be aquired online in the 100 to 250 gallon per hour range for about $20 or less.