Still need advice on this topic I posted last year. Our pebble sheen “black velvet” color has had white streaks/ fading since it was installed, Day 1, brand new last year. We’ve had water tested and have been advised by Pool supply co. that it’s in acceptable range. Is there any reason this would be happening? Could it have been too much calcium was added when they put in the interior? We had it drained and acid washed and the white streaks came right back. Please help!