Problem appears when I'm going on holiday (or want to sleep bit longer and there's no time in the morning to put some fertiliser before work ;-) ).
The off-shelf solutions are quite expensive, so I've decided to give a go peristaltic pump.
The choice I've made because peristaltic pump is probably the most accurate way for dosing liquids.
Step 1: Parts and tools
I also purchased electronic timer with the weekly schedule exact to 1 minute.
Airline enough to reach aquarium, and another small piece from pump to bottle
Rest of the bits and pieces I found at work/home:
There was 12V power supply from dead old netgear ethernet hub, and small pads/skid protectors again from the old hub
Small piece of aluminium angle bar
Piece of 5 mm plastic ~8x13cm
Pentium 4 air duct from ATX case ;-)
Bottle which fit inside air duct
Screws, nuts and washers