Do they make suction cups or other ways of affixing large tubing (like 5/8") to the wall of the tank? Also, anybody know of a place that sells them online? I think there are some heater suction cups that would work, since they go entirely around the tubing, but they are expensive, and I think that there might be a better option.

I've used these many times,and they seem to work well,but I couldn't tell you the exact sizes they hold.And best all,is that they;e pretty darn cheap. http://www.bigalsonline.com/BigAlsUS/ctl36...ewType=Category

Yeah, I have those, and they work great for the 1/4 inch tubing that fits my air pumps, but I'm going to extend the output from my powerhead, and the output from my powerhead fits the 5/8 inch tubing, but there aren't any suction cups on bigals or drfostersmith that are actually designed to do that.

Maybe something like this?

http://www.bigalsonline.com/edealinv/servl...51&ctl_nbr=3684

http://www.marinedepot.com/md_viewItem.asp...oduct=EH4015150

https://shop.trilbytropicals.com/categoryNa...g?categoryId=12