43 watt spiral bulb where

Just built my ballast for a 20 gallon nano...but I can't find a bulb for it. I want a 43 watt and today went to Home Depot, Lowes, Wallgreens, pet stores and can only find 43 watt "soft white" lighting that didn't even talk about spectrums or kelvins on the box. Is this something I just have to...