question for the electricians
 

with the magnetic cap and coil ballasts,can you use the cap off 1000watt to use on a 400awtt coil?

I would guess not. Unless a licensed electrician says different, I wouldn't try.

guess I'll be making some calls.

My guess would be no, but you could probably confirm it yourself by looking up the part #'s (if you see any on your ballast). For example, if you knew that your ballast was an Advance part # "blah blah blah" there should be a PDF on the advancetransformer.com website that lists the capacitor part# for that ballast. You then could look up whether that same part# shows up for the 1000w ballast.

But, 1) it would be a pain in the butt to look it up, and 2) I'd be kinda surprised if it was the same cap anyhow.

Not a electrician, but NO you can not substitute different cap values for ballasts. the wattage of the ballast requires a specific valued cap to operate correctly.