Problems with 8500 gal fiberglass pool

I just recently started taking care of this pool.
South florida
8500 gal
fiberglass
solar heater
3/4 hp pump [8 hrs per day]
inline tab chlorinator

i took this pool on about a month ago, when my buddy bought his house. The previous pool guy would just load the chlorinator to the top and keep the fc way above 5 ppm, and got away with it because no one ever got in the pool being as the house was empty. I dumped some water to bring down the cya the first week. Balanced chemicals to my liking using liquid chlorine.
Fc 3ppm
alk 120ppm
ph 7.4
hardness 300ppm
cya 70 ppm
phosphates under 50ppb

the pool has a very high bather load for its size [6 + people per day and a dog].
My fc would drop within a few days and water would get slightly cloudy. I started using tabs but brought my cya up to 90ppm. I tried switching to liquid until cya dropped but am getting some mustard algae now. Treated with sodium bromide but was back within a few days. Was thinking of trying the pool rx mineral but have not heard anything promising about it except from the suppliers trying to sell it to me.
Does anyone have any tips for an alternate method for caring for the pool? Any suggestions will be greatly appreciated. I hate the phone calls saying the pool is cloudy and there is a yellow film at bottom of pool.