This is our second season with our new in ground pool. Swg, 36000 gallons with raised spa and spillway. Last year I brushed the pool faithfully twice a day for the first 4 weeks. The finish was very smooth and nice last year. When we opened it this year, the spa plaster has many rough spots, sometimes catching my wife's bathing suit. The pool does not have rough spots. Any ideas? Thanks in advance!