Best possible ways to display different sizes of an item

Hi,

Well, I sell organic fertilizer, nutrient booster, plant food etc. All of my liquid items are available in 10 ml, 100 ml, 250 ml, 500 ml and 1 Liter pack.

I would appreciate, if any one advice me what would be the best way to list an item with different packing sizes.

Right now, I have 250 ml as my base listing, to this page I have added a "Bulk discount option" under which I have radio button enabled 100 ml with (- $) , 500 ml (+ $), 1000 ml (+ $) . When some one select a small size or bigger size the price updates automatically.

Thank you,
sd