How did out smooth 3M plaster get so rough

[lasawyer2]

We have a five month old pool with blue 3M plaster. Everything was fine last week and then all of a sudden, the plaster on the bottom and all the steps / jacquzzi is extremely rough, like a hard sandpaper.

What could have caused this? And can it be treated. By the way, here are the levels of our pool today:


Alkalinity: 150
Water PH: 8.0
Free Available Chlorine: 5

Thanks,
Lisa

[pool tech]

Looks like your pool is scaling. Your pH and alkalinity are to high. pH should be maintained between 7.2-7.6 alkalinity 80-120. You probably have a high calcium reading also. What you want to do is buy a large metal pool brush and about 4-6 gallons of acid. Turn off your pool equiptment at the breaker so it doesn't come on. Add 3 gallons of acid. test alkalinity the next day if its not 0 then add 2 more gallons of acid. continue doing this until you reach 0 alkalinity. During this process brush the entire pool 2-3 times per day. It could take 3-4 days for the surface to get smooth again. Once you've achieved the desired result add sodium bicarbonate to pool until you get the alkalinity and pH back in range then turn your pump back on to normal run times.

[Poolz]

Yup! Definitely sounds like scale to me. Lower pH and brushing as pool tech suggests will work. Though I would not drop TA below 50-60. I would aim for a pH of around 6.8 to get the scale softening without loosening or leaching the pool surface unnecessarily.