Ive never had VHO's before and the tank I have now came with them and its time for me to pick up a new bulb. I have 3 in there, 2 4ft whites and 1 5ft blue (I use this for dawn/dusk lighting). Its time to change out on of the whites, but I dont know what kind of bulb to get! I have amazon swords in my tank so I need to keep them happy.

Any suggestions on specific brand/model

Thanks!
Karen