Sump Advice Please?

[belzebuth]

I was just wondering what is the perfect sump size? My current setup is a 155 gallons display(reef) with a 33 gal sump. I was thinking about redoing the plumbing and maybe sizing up the sump.

I do a 15% water change every 2 weeks. My nutrient levels are pretty high and I feed a lot to keep the tangs happy:lol. More water would also probably help with the 2 to 3 degrees temp fluctuation I experience during the heat waves.

My sump is currently under the main display but the new one doesn't have to be.

Any advice would greatly appreciated.

Thanx
Andy