i tried many different silicone from different places, the one i recommend and i think is exactly the same as aquarium silicon are the one that says Doors and Windows. They cure harden up in like 30min to an hour and pretty much can be used right away but i still say wait half a day if you are inpatient to a day if u want to be 100% sure.
wat can i say, i used this silicone on my 20gallon for 8 month now, 0 problem whatsoever. I think the labeling is for the purpose of, if, anyone misuse it would not sue the company. I am currently using it on my 72bow as well. Just my experience.