Need Help Chilling

Chilling is the worst part of my brew day. I make 10g batches. Current set up is:

30' Copper Im Chiller (3/8) with whirlpool arm.

I have two march pumps, one whirlpools the wort, one pushes cold liquor through the chiller.

Also, I live in Austin - Sunday's brew session was close to 100f air temp with water temps in the mid 70s.

I push city water through the chiller with the march pump until wort drops below 120, and then I add 20# of ice. It is taking me over 45m to drop the wort below 70f.

Thinking I need to upgrade the IC to 50' (or more). Here are my questions:

1) 3/8 or 1/2" tubing?
2) copper or SS?
3) am I pissing in the wind? should I just go plate chiller?

I would like to be able to cool to lager temps, but worried about affording the ice.

As far as I know 70F is fine. Especially of you are doing ales. I usually chill to about 85-90, then rack to my Carboy. By the time the transfer is complete the Carboy feels slightly cooler than my hand so I pitch. It gets high 90's here alot, too.

I don't think a longer IC is going to help. Your water isn't cool enough. Having it pass though 25 more feet after it reaches the temp of your wort is going to do you any good.

If it makes you feel any better, my water is too cold to use instant heat water heaters. It does cool my wort down to 70 on the first pass through the Plate Chiller though.

Use a pre-chiller...get another IC, put one in the wort and one in a bucket of ice water.

Plate chillers (or even counterflow chillers) are a quantum leap past the good old immersion chiller. I live in Colorado and have well water coming into my house at 63 or so at the tap. I dumped my immersion chiller when my neighbor made us a counterflow chiller out of a garden hose, some compression fittings and 25' of 3/8" copper tubing.

I have since gone to the plate chiller because it is small and sleek for the brew rig, but anything should improve the performance of an immersion chiller (unless you go to heroic lengths of cold water bath and 50 feet of copper, etc).

Go plate and you won't be disappointed...