Noob here. We had a pool guy for about a year and recently noticed that the copper plumbing was developing pinhole leaks and had other problems with the filtration stsyem so I took a sample of the water to a local pool store to see what was going on. the chlorine was ok ph was too low to register (water was yellow same color as the chlorine side) other readings were ok except it had copper at 5 and iron at 3 they sold me two bottles of liquid metal free to get rid of the metals first. I took another sample today (a week and a half later) this time the phosphors were at 1000, iron is down to .3 and copper is at 3 the pool store wanted to sell me another two bottles of liquid metal free and a phos-free agent to add in and once the levels go down they wanted to get me on a weekly dosage of this phos-free chemical. I decided to get a second opinion from another pool store, they told me not to worry about the metals or the phosphour and that the first store is known for trying to sell their chemicals for those two things. they told me to keep the chlorine and ph levels at the correct level and not to worry about anything else and that the metals are actually good for inhibiting the growth of algae. I'm not sure what to do now so any suggestions are helpfull.
my pool is 19,000 gallons, in ground, D.E, with a spray on fiberglass liner