We made a few mistakes while learning the BBB method, and a couple years ago we had to slam the pool due to algae. Slamming seemed to cause brown staining on our pool bottom. We are now ready to drain/refill the pool, and are considering an acid wash, and then methods to prevent stains from happening again if possible. First of all, I have read conflicting things, and wonder if acid washing is safe on pebbletec? As for the stains, vitamin C crushed in a sock did not seem to release the stain. The pool techs we have seen say they see that frequently here due to our incredibly hard water (even our fill water is hard -testing out of the tap at 270-290; pool water is off the charts), and they say the calcium traps dirt into the surface. We are told an acid wash will help to remove the stains. When I refill, I have considered adding Jack's Purple Magic just for insurance in the event any stains are metal, but I hate to purchase/maintain another chemical if unnecessary. I also know that Jack's products require careful monitoring/adjusting for ph/chlorine, and we already have to be diligent due to PH rise. I appreciate any thoughts on acid washing pebbletec, and Jack's Magic or other products. I guess I just hate to pay for an acid wash if the stains are bound to reappear!