I need a bit of advice.

[morninggents]

A belated happy new year to all on here. I stupidly added some screen wash and water to my adblue tank thinking it was a rear screen wash tank. Luckily it was only about one tenth of the 1 litre screen wash, so 100 ml, and about double that amount of water. My adblue tank is 16 litres and was probably between 50% and 66% full so taking the mid point of that I reckon there is roughly 3.25% 'foreign body' in the adblue. I have not run the engine since this faux pas.
My question is what should I do? Will the screen wash and/or water do any harm if I leave it? Should I fill up with adblue to fill the tank? (therefore diluting the polutant). Should I have the adblue tank drained?
I asked the guy at my local garage what he suggested and he thought it should be OK just to fill up with adblue.
As an aside I always thought that adblue was a constant drip feed in to the fuel system but he told me that was not the case and the adblue was added at certain intervals to clean the system out. One lives and learns.