Cracks in glass can go for a while, but generally, one day, they take off. Everything depends on the direction they go in. Silicone will plug them, but not hold them. I have repaired tanks no one but me looked at (fry rearing tanks, never show tanks) with pieces of glass siliconed into place. Tanks fixed that way will hold water for years, but they aren't pretty.
If I run my sponge filters with as much air as you do, I make certain to have a very tight glass lid sitting on the rim of the tank to direct the spray down. Commercial covers will let some water out.
I've owned a lot of tanks - probably 150 plus over my years of fishkeeping. Most have been second hand, garage sale type or fish business going bankrupt types, and they have had cracks. I never trust a cracked tank not to catastrophically empty at some point. I spot a crack, I replace a tank.