The previous pool owner's kids threw some metal lawn chairs into the pool, which left some stains on the pool floor. I've had the pool for over a year now, and they don't seem to be fading, so I purchased an ascorbic acid stain remover from the pool store. They told me that I must bypass the heater when I use the ascorbic acid or else I could severely damage the heater. Is that critically important? It looks as though it could be a bit of a job to bypass it the way the PVC pipes are configured. Any advice you can provide would be greatly appreciated.