topping up method

[d2hpeter]

guys, for topping up with distilled water to the tank, can i just pour in the distilled H2O directly or what should be the correct way.
Concern is that if i were to pour in directly, there would be disturbances where certain region would hv incorrect salinity. would this cause shock to LS?

did a search but could not find answer. sorry.

[BFG]

For the pico tank? You could drip slowly.