quoting:
I need to replace some older 8'fluorescenttubes with the electromagnetic
ballasts in the fixture. Will the new slimtubes work in these fixtures? I
can't replace the ballasts or fixtures very easily.


You can still easily get regular 8' T12 "fat" tubes at any home depot,
lowes, etc. They are usually reduced wattage 60W ones though with
tend to be a bit dimmer than "real" 75W ones though. You can get a
better selection of real 75W tubes at most any electrical supply
house, if you prefer the brighter tubes.

But T8 "slim tubes" are incompatible with older electromagnetic
ballasts.