sir per my past email on copper  and greenish stains in FLA  inground pool     our pool chems are on the money  water is crystal clear  thanks for any info

our pool is in ground concrete blue crystal they call it??? 19 yrs old we have a metal or copper color stains in pool  also it looks like a green stain  but it is not algae it’s a copper / green stain???? on the bottom   and you can see as if it runs down to the deep end drain??? we do have an in ground hot tub hardly used but the water runs thru the heater then to pool I have no valve to bypass it my concern is what do I use to possibly get rid of pool copper color stain????  any idea what to use  thanks