Quick question

[keno911]

I curently have a 100 gal setup with a few fish right now. The question is do i need a power head in the tank??

[BubbaWPB]

Welcome to Reefland, keno911!

It's hard to say without knowing what you want to keep and how much circulation you have now from your filtration. The more info you give, the better advice you'll get.

[keno911]

Im running 2 emperor 400s and a coralife 220 skimmer right now

[keno911]

another question. I also have 2 snails but they are always under the sand, is that normal?

[leebca]

Sounds like the snails you have are of the Nassarius kind. They are carnivores and hide in the sand waiting to 'sense' some fresh meat to eat. Do they have a siphon tube (a single antennae-like extension) that comes out of the sand into the water above them?

You need more snails of the kind that also eat algae. The Nassarius are carnivores (and good to have to eat food missed by fishes). You also want some herbivore snails.

Flow in a fish-only tank can vary as Bubba points out. With live rock I would suggest no less than a 10x movement (that's 10 times the volume of the tank per hour). The 10 factor is a combination of the circulating pump (if you are using one) AND the powerheads. So, if your circulating pump doesn't measure up, you can add in powerheads to get the turnover up near that factor. I don't know your equipment and can't help you. But you can do the math.

Without live rock, that number can be cut back (to 5-8x). In the 70's with using only undergravel filters, and no live rock, there was no more circulation than those filters provided which was typically less than 5x.

For other things to consider in a FOWLR setup, check out:
Setting Up a FOWLR Aquarium

Want more information about snails? See this 3-part article:
http://reefkeeping.com/issues/2004-05/rs/index.htm
http://reefkeeping.com/issues/2004-06/rs/index.htm
http://reefkeeping.com/issues/2004-07/rs/index.htm

Post at Reefland often. Check out the Marine Fish: Care, Health and Disease Treatment Forum for stickies and information, too!

Good luck!