Scale build up on DiamondBrite

Just finished a drain and acid wash to remove a scaly precipitate build-up that developed on the surface of my DiamondBrite plaster finish. Removal required manual scrubbing and an acid wash.

Has anyone seen this before with DiamondBrite and does anyone have good ideas about how to prevent it? I have kept my pH 7.4 to 7.9, Ca hardness around 200, and NaCl (for SWC) at 3000 ppm so I really can't understand how I could have set up a chemical environment that is a set up for scaling.

I called the Southern Grout and Marble tech support folks who had some generic suggestions including:
1. pH 7.2 to 7.6
2. brush weekly
3. use a product called Scale Be Gone (I may have the spelling wrong) in the water.

Any thoughts about these suggestions and especially about using descalers in the water. I have been taught (via this forum) to avoid putting extra stuff in the water unless it's absolutely necessary.

Thanks in advance to any and all who can give me advice on what caused this and how to prevent it.

28K IG / DiamondBrite / DE filter / Aquarite

I'm sorry, I don't know much about the diamondbrite, although I did help someone start up their chemicals with a new diamondbrite finish. In reading the instructions the company left, it said to run the pool with slightly acidic water in the beginning. Maybe your water at the beginning was too alkaline for a while causing the scale. All of your numbers look good to me, except I would let the ph stay under 7.6 for a while, just as was suggested. I see no problem using the scale be gone for now, since you have been having a problem with scaling. This is just my opinion, as I dont' have a plaster pool.