Eel habitat

[yakfishin]

What's the best way to make a cave for a good moray residence. I'm hoping to create a couple of place where the moray will hopefully choose to stay as opposed to choosing a spot in the back of the live rock where he won't be easily seen. I have read an article on using pvc pipe to create a sort of tunnell, with two seperate entrances- one on each end of the tank, and hidden within the live rock. But wouldn't a length of pvc like that eventually become a nutrient factory? Is it best just to stack the live rock in such a way that it creates a cave and yet remains stable, and just hope he'll choose a spot where he can be seen?
Thanks for any opinions.

[SW1TCH]

For cleaning when i used a pvc tunnell i just took a power head and put it faceing in one end and it blew the debris out the other. That way it wouldnt become a nutrient factory. My eel liked to take the food in the tunnell and eat. Now i just use rock allthow now the eel doesnt seem as happy. So i might put the pvc back in when i upgrade my tank im not shure yet. I think it looks alot nicer with out the pvc.