As the topic states I am wondering what others use.
Some time ago I was strongly advised by a reputable LFS
not to use normal glass cleaner on my tanks for the reasons of contaminating the tank. I argued that I always sprayed on the towel first and then wiped. They countered with it does not matter it is still not good for the tank. So they made a sale and I bought a product called Safe& Easy made by aquarium Pharmaceuticals(expensive nontoxic glass cleaner).
Well now our 10 month old Golden Retriever takes great interest in the tank and constantly smudges it as he chases the fish to amuse himself (actually sometimes I suspect the fish of teasing him)
Anyway, I am going through glass cleaner like crazy as I am a bit particular about the cleanliness. As a result I have switched back to good old windex.
Any thoughts on this?