I agree it’s pointless to test the water chemistry.
The water chemistry can change daily, or even with-in a day. In general, pool water should be serviced and adjusted one a week.
Hot sun burns of chlorine, wind knocks leaves into the pool, water naturally evaporates.
If the buyer is in a 30 day escrow, and you are doing the inspection with in a 10 day contingency period, the buyers won’t take possession of the pool for at least 20 days. The pool will have (hopefully) been cleaned and serviced 2-3 times by them. If not, even the best water is bound to start looking a little green by then.
Unless the property is a short sale or in probate, chances are the seller has hired a pool service to keep the pool looking good for the sale.