Your phage titer tells you how many phages you have per unit volume, the CFU tell you how many bacteria you have, you need to the volume of your bacteria suspension e.g. CFU/ml - The numbers you cited fails to indicate the volumes, although they are useless without this info. Once you know this, you can easily calculate how much of your phage solution you have to add to a given volume of bacterial culture to achieve the desired excess of phages over bacteria.

Are you really sure you need 1000X more phage than bacteria? That would be quite unusual for any experiment that I can think of. Also a titer of 1.8E5 pfu/ml is really low.

But given that you know the CFU or PFU per ml for both, it is just a simple math problem to do your calculations. WIth the numbers cited above, adding 2.8 ul of cells and 1.8ul of phage would give you 1/1000 phage per cell.