Where to place my powerhead...?

[willlovesfish]

I got a powerhead and was wondering where I should place it...? Should it be in the back blowing toward the live rock, and how high or low should it be in the water? One other question is the powerhead came with an air tube and air valve for oxygenation, but the only way for it to work is for the air valve to stick out of the tank, so this means I can't put the unit very low in the water if I want to use this method. It did come with a plug if I don't want this method in which case I could put it as low as I wanted in the tank. Hope that makes sense, so which method should I use...? Any help and suggestions are much appreciated, thanks!
My tank is a 22 gallon cube shape, below is a pic.

 

[wfd1008]

i would put it behind the LR going form side to side just to get a good flow behind the rocks IMO.

 

[wfd1008]

if you want to use the air part, you could get a connector and a longer piece of tubing.

 

[willlovesfish]

Thanks for the tips. Seems blowing over the LR is the best idea so far. From what I have read though many don't use the air bubble part, guess it's just not needed because there is already enough bubbles and air coming from just the unit by itself. Unless someone can tell me otherwise I don't plan to use it.