Artificial grass is good for its purpose but that purpose is not for being wrecked by dogs. You need to decide on your priorities, Guest. If that priority is for rough dogs then you have to accept rough grassland for them to play in.

This happened us last year Guest,we, had a terrible time as our rather large Boxer ruined the garden every time he wet on the grass(specially in summer it left yellow patches, we tried every thing but nothing worked,in the end we built a "Large pen" for him and had to dig the whole lawn over and re-seed,Sorry to be a damp squid Lol hope you get it sorted out.:~))))

Can get tablets for the dog that reduce the ammonia in the urine apparently. Could find out from well known pet store or vets??