I notice that she says she is using it out on a balcony. Maybe that, and the fact that her Dog is still a puppy is helping with the smell. We have put fake grass out on our Deck for Kodi in the winter, because at his age, he has trouble with the icey steps. (Hopefully, with his new ramp, we won’t have to anymore!!!) Even though I REGULARLY cleaned it with Parvosol, by spring it smelled SO bad, we had to throw it out… and Dave had to take it to the dump in the open back of the pick-up truck!!!It sounds like you found a system that works for you! It may not be an issue since your potty tray is outside, but I looked at the fake grass trays because I thought they were kind of cute and a lot of members said they hold the smell of pee after a while, although you mentioned it hasn’t been an issue for you. Maybe because it drains and is combined with litter? I set up a makeshift litter box for my basement (my other boxes came with grates to contain the litter) and I wanted to mention that I tried a few different household items that worked well to contain litter - in case at some point you need a new “grate” and don’t want to buy a whole new litter box or grass mat. The one I liked best was rubber/silicone type gridded sink/tub liner. It kept the litter in place and allowed the right amount of drainage and was easy to clean.
We have tried fake grass litter boxes and tried every imaginable cleaning product on them without success in the house. Maybe my nose is more sensitive than others, but it sure wasn’t a product I could live with!!!