I've used tanks that have chips like that without problems BUT.... I made sure to keep the tank level and at the same constant temp, both of which can cause the chips to turn into cracks. if a crack like the top pic and bottom pick gets to halfway through the thickness of the glass its time to replace. you can get 40 gallon tanks from petsmart for $40 during the dollar a gallon sale. maybe it would be a good place for a reptile?