We want to do a no drain acid wash on our pool as well as add borax to the water. What would be the best way to do this for a 12,500 gallon pool? I wash planning to add enough acid to lower the pH to 4.0 and brush for 2-3 days. Then use the Borax to raise the pH back up. Do I have to shut down the pumps during the acid wash, or just bypass the heater? How much acid should I add? I hear some people saying 4-8 gallons, but the pool calculator is calling for 16 gallons. I don't want to waste the money by adding too much or risk ruining the finish.