The difference is the orange is the original formula with an enzyme to help clean the clothes
the green one has two forms of enzymes to clean a broader range of stains....
I just prefer to go GREEN...use all the power available to get them clean the first time
from what I have seen, they all come in the same size/use boxes....125, 180, 275, I may be wrong, but thats all I see in the stores and web site....
More on saving money....have you guys considered buying concentrates?...At Lowe's and Homo Depot, they sell ZEP products in Gallons, most from $6.99 to $11.99, of various cleaning products from window, all-purpose, tub and tile, floor cleaners...an example would be the window cleaner, cost $7.99 a gallon, take an empty WINDEX bottle and add 1 ounce of concentrate to make a 32 ounce bottle of cleaner, now for those of you who missed this, this gallon makes 128 bottles of window cleaner, how long will this last you?....and WINDEX cost about $2.99 per bottle in the stores....$2.99 X 128 = $382.72....now I like it a little stronger and mix in 2 ounces per bottle, but it's still a big savings....
note: not ALL of the products are concentrates, but still a lot cheaper than the name brand per bottle.....