urmedic911

Hello, I just found this site while inquiring about hollow sounds on pool bottom. Though it was discussed in another thread somewhat I would like to ask if anyone can help with my specific issue? I drained the pool approx two weeks ago weeks ago to get a fresh start. Water was beyond gross, algae, mold, leaves etc. I thought Id start fresh as I was also re grouting and staining coping and pool deck as well as installing or should I say replacing a broken salt water chlorinate-tor that I was told would make life much easier? Anyway, almost ready to refill now and as I was sweeping up pool I noticed a hollow sound on floor. As I was investigating with the end of a scraper handle and tapping there was a hollow sound approx 16" x 16" on the floor. No plaster is bubbling or poping up that I've seen and only some small hairline cracks are visible on floor. Can anyone tell me if this needs to be repaired prior to filling pool? Secondly, there are areas of missing grout above the border tiles just below the coping that water can intrude into. Where does the water go at that point and is it causing any issues? Just to give you weather conditions currently I live in Central Florida. Thank you for any guidance.