its 1 teaspoon per 1.5 gallons which works out to 1 and 1/3 tablespoons per 5 gallons. (remember 3 teaspoons is 1 tablespoon)
this is for a 12.5ppm concentration by the way.
when using iodophor you don't need to completely immerse the items in solution. in reality you could make a 1 gallon batch, put it in the fermenter, put a lid on it, and shake the crap out of it for a minute to be sure to coat everything. doing this is enough to coat the surfaces and sanitize effectively.
using a spray bottle full of an appropriate concentration and spraying it down very well works as well.
anything approaching, and definitely at or above 25ppm has to be rinsed as it is not considered no-rinse at that concentration. beer can be racked directly onto a 12.5ppm concentration that has been appropriately drained and air dried.
also, above 25 ppm is considered disinfecting.
the 3 levels of "anti-bacterial"
sanitized = 99.9%
disinfected = 99.99%
sterilized = 100%