Wow!! You are so lucky! How can that be possible...very clear looking water! I would be interested to know how long your first normal addition of dichlor, or whatever you use, hangs around as FC??? That would indicate if you are still brewing some 'nasties' or if the water is remarkable free of bacteria after that long closure without any maintenance! Do you have ozone and N-2? How old is the water? Usage in that water before your hospital stay?
Sure hope you are feeling better!! And that you can enjoy your tub...if you had surgery, I know that means a long time without a dip.