Setting Up Refugium & Sump ** NEED ADVICE**

[ZachAttack]

OK, I've decided to expand my reef tank from a 30g to a 90g and use the 30g for a sump/refugium. I'm fairly new at this and would appreciate having some questions answered

1) i'm going to make all the refugium things on my own, what is the best way to create a siphon that won't fail in the event of the pump quitting and the water level dropping?

2) what should I go with for a sump pump for that size of tank, where would I find one, what type is recommended, and what is the recommended turn over rate??

3) do I plumb with PVC?? I've heard rumours about it being hazardous to the marine life

Thanks guys, again I'm really new at this and it's all an adventure for me. And I'd like to learn making the least amount of fatal mistakes as possible. any tips are appreciated