Thank you so much for your reply. I try to do my best and water and mow
on a regular bases - mow (1 per week) and watering (1 per 2 weeks if
there is no rain).

The problem is with the weeds and specifically the blue ones. They seem
to be taking over the grass slowly but surely. I would prefer not to
replace the grass because it will be quite costly. This is why I was
looking for chemical solutions to fight the weeds. Still the ones I've
used so far are not help at all.

Regars,
Dimitare