Bought this home with its 13' x 26' freeform pool in FL about a year ago. Have noticed that the water level seems to quickly seep down to even with or just below some of the small cracks around the pool's top edge, and then stay stable. See pictures. I don't know what this material is, but I'm hoping to be able to fill in these small non-displaced cracks. There's ~8 of them spread around the pool, all at or above the waterline. Is filling them in a good idea, and if so, what would I use to fill them in?