ok, you guys are missing the point in trying to one up each other. As for the no drain acid, I have only had one experience with it and it was not good. As for actual acid washing DO NOT DO THIS YOURSELF. When I acid wash, I am in full protective gear with respirator, goggle, gloves, chemical covers... I post a sentry either outside the room or twenty feet away from the pool. Muriatic Acid is dangerous stuff, do not underestimate it! It can over take you and burn your lungs and everything else in no time. Also depending our your local codes it could be trouble for you, your neighbors will easily smell it and make a phone call. I would recommend the safe bet and call a tech.
Keith B. Janus
Janus Mechanical Consulting