Efficiency

I recently up graded my brewing equipment to a 100qt stock pot(25gal) my mash tun came with a 12 inch false bottom... I'm assuming that's why my efficiency is down in the low to mid 60s. Through an iodine test it proves that I have conversion. I do a double batch sparge, which drains real slowly, takes about an hour. Should I be stirring the grain while sparging? Any ideas would help!!

You defintely shouldn't be stirring while draining.  You want the husks to settle and act as a filter, so that you get clear wort.  I've found that my efficiency is better if I can keep and hold about 168F during my entire sparge process.  What are the temperature of your grain bed during sparges?

I can see why your sparge drains slowly. I mash in a 13" diameter cooler for 5-gallon batches and my grain bed is usually about 5 inches/13 cm. I stir my sparge water then recirculate until the wort runs clear before draining. It drains quickly - never timed it, so I can't tell you how many minutes in a "quickly". Your grain bed must be at least 25 inches/60+ cm. It could be a major challenge to stir that deep and would take longer than mine to drain through such a long column of grain.

In fly sparging we assume the water trickles through all the spaces and carries off most of the sugar. In batch sparging, I've always viewed it as me forcing contact between the water and the grain, allowing the grain bed to settle, then draining off the sugar-water. If you can't stir that deep grain bed, you have to hope the water trickles through evenly and brings most of the sugar with it. I'd suggest at least trying to stir as deep into the grain bed as possible, recirculating til clear, then draining.  As I'm trying to visualize this I'm seeing a 25-inch grain bed under 10 inches of hot wort; that's going to be a major challenge.

This link may help with one approach to batch sparging. Denny uses a rectangular cooler, so his grain bed is MUCH thinner and easier to stir. He recirculates by hand.
      dennybrew.com     

Please, let us know how you solve this problem.

One of the problems of changing your mashing size and geometry is you may have to change your milling and water ratio. Increasing the gap of the mill to give you a coarser grind will give you more hulls to improve your batch sparging times but this may lower your efficiency. So to counter this you will have to increase your mash time and make sure your water ratio isn't too thick. You don't want your mash looking like wet cereal when you stir it you want it watery.
You don't mention how you are heating your mash or maintaining mash temp. Strike water only, recirculating, and or direct heat.
You would make out better if your false bottom covered the entire bottom.
Good luck!

False bottom means nothing for batch sparge efficiency.... Vis-a-vis Dennys braid pigtail. Nor does bed geometry.

That is, UNLESS the bed is compacting and you are leaving too much wort in the mlt. Which is what it sounds like might be happening. I wouldn't change your crush... Just Add 1/2 lb of rice hulls to your mash and see what happens. Open your mlt valve a little less and let the grain bed set gently before opening the valve all the way.

Tom is right. When you fly sparge you want to keep an inch or so of hot liquor (sparge water) on top of the grain bed. I always felt like the buoyancy of the grain husks keeps the mash separated to allow the sparge water to channel through the grain bed and rinse the mash out better. I don't use rice hulls but with some systems it will help. So, just slow the flow into the boiler and turn up the sparge to have a constant layer of water at the top of the grain bed. If you do stir the mash it should only be at the very top. I do this to redirect the flow a bit but never disturb the bottom 3/4 of the grain bed. You want to avoid the evil tannins.