Brown/yellow stain overnight

[Colleen in PA]

My 16'x32" inground pool was a little cloudy and it's been hot so I added shock and a cup of stabalizer before I went to bed on July 4. I woke up to see the entire pool and steps stained brownish yellow! I went to our pool place and had the water tested. They had me increase PH and alkalinity(added 20 lbs). The water was perfect, no metals they said so they gave me a container of stain out today. I broadcasted it, waited 5 hours and now I have spotted steps and 3 or 4 visable patches of white on the bottom about 2' around. I backwashed my pool for the 10th time and what came out clear before is the worst shade of dark, almost burnt red I have ever seen! The water in my pool was clear,chlorine was 11,everything else was good. Now it looks dark brown and I can't see the bottom. What was in the hth stabalizer that could have reacted and stained the pool so bad? How can I clean such a huge area ? I've had the pool over 40 years and I've never seen anything like it. It has my pool guys stumped. Any ideas? I need help, please!

[saovietxulynuoc]

You should use the PAC - poly aluminum chloride after shock chlorination. Residue will settle to the bottom and you use hygiene kits to remove