Bubbles and SCWD's and Sumps (oh my!)

[Cearbhaill]

I'm on my second wave of reef keeping research (current topic sumps) and feel as if my head is going to explode!
But I am determined to research this project thoroughly and try to avoid as many mistakes/bad purchases as possible.

I have one "just curious" question and one plumbing question-
Why all the avoidance of bubbles with the baffles and sponges in the sump? Is it just to avoid them visually or do bubbles actually cause some sort of problem in a reef/marine tank?

Why does everyone use PVC for the plumbing instead of flexible tubing?
Specifically for a return pump from my sump- why can't I use tubing to connect to a SCWD then just run tubing into the tank? Seems it would be easier to work with than PVC- I'd assume it's because of structural integrity? PVC is just stronger and more durable? Less prone to blow out/off?

BTW I've almost convinced myself to forget a HOT skimmer and rig myself up a sump- thinking of making one from an old 30g breeder tank.
Please tell me I can do this :confused:

[liquafaction]

my understanding is that some corals will die being subject to air (bubbles), like sponges. I had a problem with a berlin skimmer putting out to many bubbles, but once I figured out how to adjust it, that stopped.

I think PVC is just a personal preference. I like using pvc more because it is ridgid, and permanant. Flex hose is easy to set up, but I like the security of something being glued together, and not blowing off. I had some flex hose come loose from the bottom of my internal sump before. My internal sump is about 5 gallons, and five gallons of water on the carpet is a mess. Needless to say, I glue now.

I also do not like HOT items, other than ease of removing and cleaning. I personally do not like everything hanging off of my tank. An external sump is a possable alternative. I enlarged my internal sump to fit my skimmer, and extra powerheads. Remeber this, if you do not have an internal sump, or an overflow pipe (like inside a toilet) and you power goes out, or your sump pump quits, all the water from your tank is going to empty into your floor.